Barriers to the Implementation of Iran’s Clean Air Act: A Policy-Oriented Scoping Review

Abstract

Air pollution remains a serious environmental and public-health issue in Iran. Despite the Clean Air Act (CAA), enforcement is limited and compliance is weak. This 2025 scoping review outlines major barriers to CAA enforcement and proposes evidence-based policy actions. Multiple databases including Scopus, Web of Science, PubMed, and Google Scholar were searched and Policy documents, institutional reports, and legal texts were identified through Google and official organizational websites. Finally, a thematic analysis was conducted on the data using a four-dimensional conceptual framework. The data were categorized into four main categories of challenges. In the cultural, information and evidence domain, key issues included low policy priority for air pollution, weak public awareness, insufficient transparency, and lack of evidence for policymaking. Governance-related challenges involved institutional fragmentation, limited authority of the Department of Environment (DOE), multiple actors without coordination mechanisms, weak enforcement, and absence of performance metrics. Financial constraints included reliance on public budgets, lack of sustainable revenue sources, project interruptions due to budgetary constraints, and absence of cost–benefit models. Technical and infrastructural issues included lack of a data-governance system, absence of mandatory data and equipment standards, no technological roadmap, and weak industrial technology and monitoring infrastructure. Governance and institutional challenges represented the predominant share of factors hindering the CAA implementation in Iran. Addressing these challenges requires stronger political commitment, governance reform, sustainable financing, integrated data and monitoring systems, enhanced technical infrastructure, and evidence-based policymaking. A comprehensive, intersectoral, and long-term redesign of air-pollution control mechanisms in Iran is essential.

Introduction

Air pollution is a major environmental problem and a serious public-health threat in Iran and globally. According to WHO, it causes millions of premature deaths annually and is the largest environmental health risk. ¹ Air pollution has also been identified as a significant contributor to the escalation of climate change in the Middle East. ² Iran—particularly its major metropolitan areas such as Tehran—continues to confront severe air pollution challenges, with concentrations of particulate matter (PM₂.₅ and PM₁₀) frequently surpassing international standards by wide margins. ³ Such elevated pollution levels are associated with significant increases in morbidity and mortality, especially from cardiovascular and respiratory conditions.^3,4 Iran’s environmental health crisis underscores the need for policymakers to formulate and implement targeted strategies to address this growing threat. Local experts have emphasized organic agriculture and afforestation as key interventions to mitigate environmental degradation. ⁵ There is also growing potential for applying artificial intelligence to predict climate-related phenomena, especially those linked to air pollution. ⁶

In Iran, the Clean Air Act (CAA) was enacted in 2017 as the third generation of such legislation to provide comprehensive mechanisms for controlling, monitoring, and reducing air pollution. ³ The first generation of air-quality legislation, drafted in 1995, assigned primary responsibility for air-quality management to the Department of Environment (DoE). The CAA comprised six chapters and thirty-six sections, and it categorized sources of air pollution into three main groups: motor vehicles; factories, workshops, and power plants; and commercial, domestic, and other miscellaneous sources. ⁷ In such context, Iran is considered one of the few Middle Eastern countries that has explicitly prioritized air quality, as reflected in the development and implementation of Air Quality Action Plans (AQAPs). ⁸ Yet, despite successive legislative reforms, the gap between law and implementation has widened.

Existing literature indicates that Iran’s air-pollution and environmental regulations remain inadequate and insufficiently comprehensive. Furthermore, they are characterized by a lack of transparency and consistency, limiting their effectiveness in practice. ⁹ Their limited effectiveness is largely attributed to weaknesses in implementation, oversight, and enforcement. ³ In this context, despite the CAA’s ambitious goals, its implementation has been hindered by multiple structural, institutional, financial, and technical barriers. Official assessments, including audits by the Supreme Audit Court, have evaluated overall implementation as weak and below 10%.^10,11 A report by the Parliament Research Center classified the implementation performance of the Act’s mandates into good, moderate, and weak, finding only 4 mandates with good performance, 11 moderate, and 14 weak (Table 1). ¹² Nevertheless, analyses of pollutant levels before and after the Act’s implementation suggest that—even with limited enforcement—anthropogenic emissions have been partially reduced. ¹³

Table 1.

Implementation Performance status of CAA mandates ¹²

Good performance	Moderate performance	Weak performance
Development of green belts in dust-affected cities and villages; industrial emission inspections and establishment of HSE units; allocation of green space in industrial facilities; annual technical inspection of boiler rooms.	Legal enforcement and dedicated judicial branches for air-pollution offenses; establishment of the national natural-disaster early-warning network; education and public awareness for air-pollution control; allocation of environmental water rights; provision of standard vehicle fuel; online monitoring of major industrial emissions; industrial emission reduction and restriction; environmental impact assessment in industrial expansion; vehicle technical inspections; production and import of standard vehicles; establishment of air-pollution emergency committees.	Allocation of Act-generated revenues to air-pollution-control programs; control of electromagnetic pollution; noise-pollution control; expansion of anti-desertification programs; international coordination for dust-storm management; expansion of green space; urban expansion conditional on environmental studies; prohibition of waste burning outside designated sites; development of clean energy; relocation of polluting industries; use of standard fuel in industries; modernization of public transport; expansion of traffic-restriction schemes; replacement of old vehicles.

Given the persistent severity of air pollution and the limited effectiveness of existing legal instruments, a deeper understanding of the structural and implementation barriers of the CAA is essential. Despite extensive challenges associated with the CAA, the existing body of knowledge remains fragmented, multidisciplinary, and lacking an integrated synthesis. Most available studies address only isolated technical, legal, or institutional aspects, and no prior review has systematically assessed CAA implementation barriers using a coherent analytical framework.^3,9-11 This fragmentation has prevented the emergence of a cohesive understanding of why the CAA has underperformed despite extensive institutional mandates. This knowledge gap hampers accurate assessment of the situation and limits the development of robust policy recommendations. Accordingly, this study seeks to identify, categorize, and systematically analyze the challenges and deficiencies inherent in the CAA and its implementation in Iran. By consolidating key findings from existing documents and scholarly research, the study aims to provide a clear and holistic understanding of clean-air governance in the country, thereby supporting evidence-informed policy reform. The insights generated may assist policymakers and stakeholders in developing long-term strategic plans to address implementation challenges and barriers and enhance the efficiency and effectiveness of the CAA and comparable legislative frameworks in Iran and similarly situated contexts.

Methods

This study employed a scoping-review methodology in 2025, following the PRISMA extension for scoping reviews (PRISMA-ScR) guideline, to identify, categorize, and systematically analyze policy documents, official reports, and scholarly studies pertaining to the challenges associated with Iran’s CAA. This approach was used as the scoping review is presented to be suitable for fields with dispersed, multidisciplinary, and emerging evidence, enabling a comprehensive view of current conditions, policy gaps, and research priorities.^14,15

The review followed the five-stage Arksey–O’Malley framework and its enhanced version by Levac et al.^16,17: defining the research question; identifying information sources; selecting eligible sources; extracting and organizing data; and thematic analysis and reporting. The primary research question was formulated as follows: “What are the substantive and implementation-related challenges of the CAA in Iran?”

Data Collection

A systematic search was carried out in the databases Scopus, Web of Science, PubMed, and Google Scholar. Additional relevant documents, including policy documents, institutional reports, and legal texts, were identified through manual searches of reference lists, Google search, and key institutional websites. The search period (2015–2025) was chosen to focus on recent studies and documents. The search terms combined keywords related to air pollution, policy/legislation, and the geographical context of the study. The complete search strategy is presented in appendix 1.

Appendix 1.

Search Strategy and Reviewed Databases

Database	Search Strategy	Results
PubMed	(“Air Pollution”[Mesh] OR “Air Pollutants”[Mesh] OR “Air Pollution”[TIAB] OR “Air Pollutant*”[TIAB] OR “Urban Air Pollution”[TIAB] OR “Air Quality”[TIAB] OR “Particulate Matter”[Mesh] OR “Particulate Matter*”[TIAB] OR “PM2.5”[TIAB] OR “PM10”[TIAB] OR “Black Carbon”[TIAB] OR “Nitrogen Dioxide”[TIAB] OR “NO2”[TIAB] OR “Sulfur Dioxide”[TIAB] OR “Sulphur Dioxide”[TIAB] OR “SO2”[TIAB] OR “Carbon Monoxide”[TIAB] OR “CO”[TIAB] OR “Ozone”[TIAB] OR “O3”[TIAB] OR “Vehicle Emission*”[TIAB] OR “Environmental Exposure”[Mesh] OR “Environmental Exposure”[TIAB] OR “Dust”[TIAB] OR “TSP”[TIAB]) AND (“Public Policy”[Mesh] OR “Public Polic*”[TIAB] OR “Government Polic*”[TIAB] OR “Environmental Policy”[Mesh] OR “Environmental Polic*”[TIAB] OR “Climate Polic*”[TIAB] OR “Health Policy”[Mesh] OR “Health Polic*”[TIAB] OR “Government Regulation*”[TIAB] OR “Emission Control”[TIAB] OR “Air Pollution Control”[TIAB] OR “Regulation*”[TIAB] OR “Legislation*”[TIAB]) AND (Iran[MeSH Terms] OR Iran[Title/Abstract]) AND (“2015”[Date - Publication] : “2026”[Date - Publication])	112
Scopus	(TITLE-ABS-KEY ( “Air Pollution” OR “Air Pollutant*” OR “Urban Air Pollution” OR “Air Quality” OR “Particulate Matter*” OR “PM2.5” OR “PM10” OR “Black Carbon” OR “Nitrogen Dioxide” OR “NO2” OR “Sulfur Dioxide” OR “Sulphur Dioxide” OR “SO2” OR “Carbon Monoxide” OR “CO” OR “Ozone” OR “O3” OR “Vehicle Emission*” OR “Environmental Exposure” OR “Dust” OR “TSP” ) AND TITLE-ABS-KEY ( “Public Polic*” OR “Government Polic*” OR “Environmental Polic*” OR “Climate Polic*” OR “Health Polic*” OR “Government Regulation*” OR “Emission Control” OR “Air Pollution Control” OR “Regulation*” OR “Legislation*” ) AND TITLE-ABS-KEY (Iran) AND ( PUBYEAR > 2014 ))	342
ISI	TS=(“Air Pollution” OR “Air Pollutant*” OR “Urban Air Pollution” OR “Air Quality” OR “Particulate Matter*” OR “PM2.5” OR “PM10” OR “Black Carbon” OR “Nitrogen Dioxide” OR “NO2” OR “Sulfur Dioxide” OR “Sulphur Dioxid”OR “SO2” OR “Carbon Monoxide” OR “CO” OR “Ozone” OR “O3” OR “Vehicle Emission*” OR “Environmental Exposure” OR “Dust” OR “TSP”) AND TS=(“Public Polic*” OR “Government Polic*” OR “Environmental Polic*” OR “Climate Polic*” OR “Health Polic*” OR “Government Regulation*” OR “Emission Control” OR “Air Pollution Control” OR “Regulation*” OR “Legislation*”) AND TS=(“Iran”) AND PY=(2015-2026)	157
Google Schoolar	​	-
	Results before removing duplicates	611
	Duplicate results	182
	Final results	429

The search was performed on the titles and abstracts of studies indexed within mentioned databases. All retrieved records were imported into EndNote, and duplicates were removed. During the screening process, titles and abstracts were initially examined to exclude irrelevant studies. Subsequently, the full texts of the remaining articles were thoroughly reviewed, and studies providing relevant data addressing the research question were selected for inclusion. Screening was conducted independently by two authors, with a third author overseeing the process to ensure validity and minimize bias.

Inclusion and Exclusion Criteria

Included sources directly addressed the challenges, barriers, or deficiencies related to Iran’s CAA and encompassed policy, institutional, governance, technical, or implementation aspects. These sources comprised official policy documents, performance reports, policy analyses, interdisciplinary studies, and legal assessments. Only sources published in Persian or English were considered. Sources were excluded if they lacked direct relevance to air pollution governance or legislation, were duplicates, non-scholarly, non-research materials, or if full-text access was unavailable.

Data Analysis

Data were analyzed using thematic analysis to identify key concepts, themes, and patterns related to barriers or deficiencies of the CAA. The sources were organized, coded, and analyzed using the MAXQDA software. A formal data-extraction form was not used, as is common in policy-oriented scoping reviews. Instead, all eligible documents were imported directly into MAXQDA, allowing full-text qualitative coding consistent with the Arksey–O’Malley and Levac methodological frameworks. This approach has been widely adopted for multidimensional policy documents where predefined extraction tables may limit the depth and flexibility of concept identification. Using qualitative-analysis software enabled systematic coding, ensured transparency, and provided a structured audit trail, which functionally replaces the need for conventional extraction sheets.

The thematic analysis was conducted independently by two researchers. Disagreements were resolved through discussion or, if unresolved, by consultation with the third reviewer. A third researcher supervised the process. Such supervision lowered the level of bias in the analysis. Codes were reviewed, merged, refined, and finalized through multiple rounds of analysis. Consistent with contemporary scoping-review guidance (e.g., Levac et al.; Peters et al., JBI), thematic analysis was applied to map key concepts and patterns rather than to generate interpretive or explanatory theory. Thematic organization in scoping reviews is well-established for synthesizing heterogeneous policy and legal sources. The qualitative analysis in this study was descriptive and categorizing in nature, aligned with the purpose of scoping reviews to map existing evidence, not to assess causality or conduct interpretive synthesis.

The thematic analysis followed an inductive–deductive hybrid and iterative approach. Although coding was conducted inductively, the final organization of themes drew on a conceptual framework from environmental governance literature. In the final stage, the identified themes were organized within a four-dimensional conceptual framework consisting of “governance and institutional,” “information, evidence, and culture,” “technical and infrastructural,” and “financial and economic” dimensions. This framework was derived from the environmental governance and public policy literature which has been used in prior analyses of environmental policies and governance systems. ¹⁸ Its application allowed systematic classification of challenges across design, implementation, and oversight levels, ensuring coherence in the analytical process.

Results

As illustrated in Figure 1, an initial search of the databases identified 611 records, with an additional 23 documents retrieved from other sources, of which 182 were duplicates. During the screening of titles and abstracts, 418 references were excluded due to their irrelevance to the research topic, as described earlier in the Methods section. Following the screening process, 34 full texts were carefully reviewed. Of these, 7 were excluded for being unrelated to the research question, 5 were deemed low quality due to the absence of a research basis, and 1 was excluded because the full text was unavailable. Ultimately, 21 sources were included in the analysis. Among these, five were published in English and sixteen in Persian; fourteen were peer-reviewed studies, and seven were official reports (Table 2).

Figure 1.

Summary of challenges and policy recommendations

Table 2.

Bibliography of the included documents

No.	Title	Authors	Source	Type	Yr.
1.	Long-term perspectives on land-use changes and air pollution policies in Iran: a comparative analysis of regional and global patterns in atmospheric pm2.5	Yousefi et al.	Journal of Environmental Management	Journal Article	2025
2.	Air pollution governance system: application of organizational network analysis of clean air law enforcement	Ramezani & Rahimi	Natural Resources Governance	Journal Article	2024
3.	Principles and legal requirements in line with management of haze	Khazaei	Recent Developments in public Law	Journal Article	2024
4.	Supervision challenges of department of environment in enforcement of proper implementation of CAA	Faryadi	Administrative Law	Journal Article	2024
5.	Pathology of article (6) of the CAA in the field of vehicle technical inspection	Rezaei, Ahmadi-Fini & Bagherpour	Parliament Research Center of The Islamic Republic of IRAN	Report	2024
6.	Review and brainstorming on the challenges of the CAA	Beikinejad & Ghargchian	Yazd Province Governance Think Tank	Report	2024
7.	Air pollution in Iran: the current status and potential solutions	Taghizadeh et al.	Environmental Monitoring and Assessment	Journal Article	2023
8.	Evaluation of criminal protection of clean air and existing challenges	Razaghi	Modern Interdisciplinary Research in Law	Journal Article	2023
9.	Study of the CAA's implementation measures and solutions - The law's shortcomings	Ashjaei & Soleimani	Parliament Research Center of The Islamic Republic of IRAN	Report	2023
10.	CAA implementation requirements with emphasis on credits	Ashjaei & Soleimani	Parliament Research Center of The Islamic Republic of IRAN	Report	2021
11.	Pathology of the CAA – part one: performance	Ashjaei & Soleimani	Parliament Research Center of The Islamic Republic of IRAN	Report	2021
12.	Review of studies on the origin of air pollution in the country along with providing improvement solutions	Zare & Taghvai	Parliament Research Center of The Islamic Republic of IRAN	Report	2021
13.	Challenges of implementing polluter pays principle in Iranian CAA	Mulaee	Journal of Legal Studies	Journal Article	2020
14.	Examining the government's obligations under the “right to clean air”: case study of the legislative system of the Islamic republic of Iran	Ghamami & Taghinezad	Journal of Eslamic Human Rights	Journal Article	2020
15.	Irregularities and weaknesses of the CAA compared to the prevention of air pollution act	Soudmandi	Public Law Researsh	Journal Article	2020
16.	Improvement of the criminal provisions and innovations of the CAA compared to the prevention of air pollution act	Soudmandi	Journal of Criminal Law Research	Journal Article	2019
17.	Policy analysis of urban air pollution reduction in Iran in the scope of political ecology	Bohloli & Malek-Afzali	Iranian Journal of Public Policy	Journal Article	2019
18.	Comparing carbon dioxide reduction strategies in Iran and the European union transportation sector	Eskafi	Asian Journal of Water, Environment and Pollution	Journal Article	2018
19.	Investigating the influence of traffic emission reduction plans on Tehran air quality using wrf/camx modeling tools	Shahbazi et al.	Transportation Research Part D: Transport and Environment	Journal Article	2017
20.	Laws and legal safeguards governing the handling of air pollution in industrial city of arak in Iran, and its comparison with international norms	Shiravand	Journal of Fundamental and Applied Sciences	Journal Article	2017
21.	Comparative study of countries' governance structures in reducing and controlling air pollution and providing solutions for Iran	Soleimani & Cheraghi	Parliament Research Center of The Islamic Republic of IRAN	Report	2017

The data were analyzed and organized into four domains of barriers and challenges, as shown in Table 3: (1) Information, Evidence, and Culture (five items); (2) Governance and Institutional (eight items); (3) Financial and Economic (five items); and (4) Technical and Infrastructural (six items). The analysis also distinguished between two levels of challenges—implementation and legislative design—comprising nine and fifteen items, respectively.

Table 3.

Barriers to the Implementation of Iran’s Clean Air Act

​	Information, Evidence & Culture	Governance & Institutional	Financial & Economic	Technical & Infrastructural
Implementation level	Low awareness and low policy priority for air pollution; cultural resistance of industries to standards.	Sanctions and weak international engagement; inefficient and fragmented public structures; non-compliance, neglect of legal duties, and low transparency of responsible agencies.	Insufficient and irregular financial resources and budget allocation.	Outdated equipment and technologies; low efficiency of public and private industries.
Legislative design level	Paternalistic approach with limited public participation, awareness-building, and oversight; ambiguity and gaps in the Act; limited use of evidence, climatic diversity, pollutant shares, and policy impact/prioritization.	Lack of a strong, coordinated governance system; weak enforcement mechanisms and limited use of incentives; inappropriate exemptions; absence of measurable performance criteria.	No stable or dedicated funding; excessive reliance on general budgets; lack of an economic cost–benefit model for pollution reduction; no transparent mechanism for revenue generation and expenditure under the Act.	No integrated data-governance and monitoring system; absence of binding standards for data and equipment quality; unclear technical responsibilities across agencies; no technology roadmap and no provisions for adopting modern monitoring systems.

Information, Evidence, and Cultural Challenges

Air pollution remains a low policy priority, despite decades of legislation and worsening pollution in major Iranian cities, largely due to overriding economic crises.^10,19 Manifestations include insufficient investment in clean transport, ²⁰ inadequate monitoring equipment, ¹¹ and weak cooperation by industries and citizens which shows that air pollution is not a top priority culturally. ²¹

A core root is the Act’s minimal emphasis on public participation and awareness. ²⁰ Legal assessments describe a paternalistic, state-centric approach that concentrates responsibilities within government bodies while neglecting civil society, private-sector engagement, and cultural mobilization, shaped by Iran’s closed governance structure. ²² Accountability tools such as transparency, public access to information, independent oversight, and collective legal standing are largely absent; neither DOE nor Non-governmental organizations (NGOs) are authorized to litigate on behalf of the public,^22,23 weakening social monitoring. ¹¹

Information gaps are intensified by substantial ambiguities in the Act. Legal analyses identify missing foundational concepts—e.g., the right to clean air—leading some provisions to treat air as a tradable commodity where pollution becomes payable via fines. ²² The Parliamentary Research Center reports widespread vagueness: unclear deadlines, undefined quantitative targets, ambiguous responsibilities, and not considering all available aspects and solutions. ¹⁹ For instance, Article 4 mandates adopting “international norms” for vehicle emissions without specifying which standards. This report claims that the main reason for such ambiguities is that the scientific path of drafting the law was not followed. ¹⁹

The Act’s drafting lacked baseline assessments, pollution sources apportionment, or impact evaluation, indicating non-evidence-based legislation.^19,20 This produced unrealistic provisions: e.g., relocation/closure mandates for polluting industries ignore socioeconomic feasibility and employment effects, causing non-enforcement. ²³ Absence of policy prioritization allows low-impact, highly visible interventions—such as long-standing traffic-zone schemes poorly evaluated —to overshadow essential measures, creating an illusion of progress.

Insufficient evidence also caused neglect of climatic and ecological diversity: green-space mandates do not differentiate between arid provinces (e.g., Yazd) and forested regions (e.g., Mazandaran); also urban geography and natural self-purification capacity are ignored. ²⁰ Overall, despite extensive scientific studies on air pollution in Iran, policymakers neither demand nor systematically use them, preventing integration of evidence into policy. ²⁴

Governance and Institutional Challenges

Iran’s macro-political and governance conditions have created a highly complex situation that affects many subsystems and underlies numerous national problems. Severe sanctions and poor international relations have sharply weakened the economy, pushing livelihood issues to the top of the agenda and relegating environmental and even public-health concerns. Under these strained political and financial conditions, limited international cooperation and budget constraints have prevented industries from upgrading, adopting clean technologies, and reducing emissions. ²⁵ Institutional challenges, however, extend beyond foreign relations, as domestic agencies also suffer from significant inefficiency and lack of coordination. Fragmented, siloed operations, concentrated authority and centralized decision-making, low transparency, and limited democratic oversight are prevalent.^10,19-21 Institutional instability—including frequent managerial turnover, inconsistent political commitment, and shifting organizational mandates—creates discontinuity and weakens long-term implementation. Moreover, the DOE, as the main body responsible for the CAA, lacks sufficient authority, resources, and oversight tools to compel other agencies to comply.^11,19 This institutional inefficiency and weak oversight have led to widespread subjective interpretations of the law, non-performance and violations by responsible agencies. ¹⁹ Examples include issuing fake vehicle inspection certificates for polluting cars and failing to inspect government vehicles. ²⁶ Another case concerns Article 26 of the CAA, which required the Meteorological Organization to complete the national hazard-warning network within two years; yet after six years no meaningful action was taken, prompting the Supreme Audit Court in 2022 to open an investigation into the agency’s non-performance. ¹⁰

Part of these institutional problems stems from the design of the law itself. First, the role of international cooperation in addressing air pollution—especially for technical expertise, technology transfer, equipment, and foreign investment—was overlooked.^20,27 Second, no strong, coherent governance system for implementation was designed. ²⁷ Since the law assigns responsibilities to multiple bodies—such as the Ministry of Interior, Traffic Police, Ministry of Industry, Ministry of Roads, Judiciary, and state media—effective implementation requires high interagency coordination. Yet mechanisms for such coordination or for enabling the DOE to supervise and hold agencies accountable are neither defined nor supported by sufficient authority, capacity, or resources.^{11,20,21,26,28} For instance, Article 11 refers to industrial construction, expansion, production-line changes, and relocation to DOE approval, but the two-step review process effectively limits the agency’s oversight power. If the DOE denies approval, a provincial commission—mainly composed of development-oriented bodies—can overturn its decision, making reversal of environmental objections highly likely. ¹¹

The law also assigns heavy obligations to agencies without ensuring the necessary implementation infrastructure. According to the principle of proportional authority and responsibility, the DOE can demand compliance only when it has adequate means and authority. ¹¹ Additionally, in several cases the law does not specify the appropriate implementing body.^19,23

Another substantive weakness of the law is the lack of adequate and clear performance metrics. For example, declaring an air-pollution emergency depends on the presence of a “serious threat” to human health and the environment, yet the criterion for “serious threat” is undefined. ²³ Similarly, many provisions lack measurable, quantitative targets for assessing conditions or agency performance, enabling agencies to present routine activities as fulfillment of legal duties.^20,22

The law also suffers from weak enforcement mechanisms. Because it ignores evidence on pollutant shares, penalties are not meaningfully linked to actual pollution levels or damages, and many sanctions lack deterrent effect. In practice, pollution fines—especially for industries—function more as government revenue streams than deterrents. This creates institutional conflicts of interest and reduces the state’s incentive to eliminate pollution sources, as polluting industries become financially beneficial.^22,28 Moreover, there is no requirement for transparency regarding government revenues from these fines or how they are spent. ²²

Insufficient use of incentives and appropriate criminal provisions further reduces deterrence.^19,23,26 Problematic exemptions, alternative penalties, and carve-outs from legal requirements worsen the situation. All industrial, production, and even service-sector activities must fall under environmental oversight, as restricting the authority of the DOE would inevitably lead to irreversible consequences. ²⁹

Financial and Economic Challenges

As noted earlier, political conditions, budget deficits, and financial constraints have undermined implementation of the CAA. Partial execution of air-pollution control programs had initially helped contain pollution, but after 2018 most measures were halted due to budget cuts and lack of financial allocation—worsened by sanctions. Given the natural annual rise in emissions (from increasing pollution sources, aging fleets, rising energy consumption, etc.), pollutant concentrations began to climb again. ¹²

The law also lacks provisions for stable funding.^20,30 Heavy dependence on the general budget has led many legal mandates to remain unimplemented or only partially carried out, as agencies cannot fulfill duties under budget limitations or non-allocation. Executive bodies also lack discretionary funds beyond their annual budget plans. Furthermore, the absence of dedicated and sustainable revenue sources—such as pollution charges, green taxes, market-based instruments, or private-sector participation—means no independent financial backbone exists for continuous air-quality programs.^11,19 Additionally, the lack of an economic model for cost–benefit assessment prevents policymakers from comparing the economic gains of pollution-reduction actions (e.g., fewer deaths, energy savings, productivity gains) with their implementation costs. As a result, economic decision-making in this domain is often intuitive, non-analytic, and financially unsupported. ²⁰

Technical and Infrastructural Challenges

Inadequate technical infrastructure is a major barrier to implementing the law. Key issues include the lack of sufficient technologies and tools for collecting, integrating, standardizing, and analyzing air-pollution data ²¹ ; outdated industrial technologies (e.g., in the automotive sector); widespread use of old, high-emission vehicles; poor fuel quality; and the high costs of hybrid and electric cars due to import duties and taxes. ²⁵

As in other dimensions, the law’s technical design is also weak. The absence of an integrated data-governance and monitoring system has led each agency to produce fragmented, inconsistent, and non-comparable datasets, leaving no accurate, up-to-date, and unified picture of air quality. Without such a system, performance evaluation, trend prediction, and evidence-based decision-making are severely undermined. ¹⁹ The lack of binding standards for data quality, measurement devices, and monitoring equipment allows agencies to use varying—and sometimes unreliable—methods. This inconsistency reduces data credibility and obstructs comparison and verification. Moreover, unclear technical roles and responsibilities across agencies create task overlap, institutional unaccountability, and coordination problems; it is unclear who should procure equipment, calibrate it, or validate and publish the data.

The absence of a technological roadmap and mandatory adoption of modern technologies and continuous monitoring systems has left the country with outdated, reactive technical capacity. Without planning for tools such as remote sensing, low-cost sensors, artificial intelligence, and real-time monitoring platforms, the technical foundation required to implement the law remains structurally insufficient. ³¹ These weaknesses collectively mean that even a well-designed CAA cannot succeed without the necessary technical and data infrastructure.

Discussion

According to the study findings, governance and institutional challenges and barriers accounted for the largest proportion of factors associated with the implementation challenges of the CAA in Iran, representing 33% of the data. At the legislative design level, the study recorded the highest number of challenges and barriers, with this category representing 62% of the dataset. These findings align with existing literature, which indicates that Iran’s environmental policymaking is impeded by legislative, institutional, and political obstacles, such as inadequate oversight and insufficient enforcement of regulatory frameworks. The DOE is reported to be characterized by structural deficiencies, ill-defined objectives, absence of a coherent long-term strategy, and reliance on capricious political directives. Furthermore, the government’s prioritization of economic growth over environmental conservation has resulted in disjointed policies, exacerbating environmental threats including water scarcity and pollution. ³²

Recent nationwide assessments demonstrate the persistence of severe particulate and gaseous pollution episodes across major Iranian urban and arid zones, mainly driven by anthropogenic emissions and transboundary dust storms.^33-35 These studies evidence critical exceedances of WHO limits and underline inefficient control policies. Parallel investigations highlight significant carcinogenic and non-carcinogenic health burdens, particularly respiratory and cardiovascular disorders, as well as heavy-metal–related risks in industrial and dust-prone regions.^36-38 Collectively, these findings emphasize that air pollution and dust remain major, unresolved environmental and public-health challenges across Iran. In this regard, the literature reports that air pollution has been remained a low priority among policymakers despite decades of crisis and the extensive scholarly evidence on the context. Prior research confirms that severe economic problems shift managerial priorities toward livelihood issues, sidelining environmental concerns.^10,19 Consequences include neglected clean transport infrastructure, insufficient monitoring equipment, and limited industry and public engagement.^11,20,21 This stems from weak public culture and an authoritarian law design limiting civil participation and ignoring transparency and accountability mechanisms. ²² Theoretically, this contradicts participatory governance, where transparency and participation are core to policy accountability and effectiveness.^39,40 In this regard, Cultural challenges and barriers constituted another set of obstacles inhibiting the implementation of CAA in Iran. Notably, while paternalism has been recognized as a culturally embedded practice that is, interestingly, accepted by many members of the general population, limitations within the governance system and its infrastructure have also been shown to substantially reinforce paternalistic tendencies in Iran.^41,42

Another challenge reported by our study was legal ambiguity and the absence of an evidence-based approach. Ignoring fundamental principles, such as the right to clean air, and failing to define quantitative targets and precise guidelines render the law open to multiple, sometimes arbitrary interpretations.^19,22 Neglecting scientific studies on pollutant shares and intervention prioritization has led to prolonged, ineffective policies, e.g., traffic schemes, without outcome evaluation.^20,43 In this regard, several strategies have been proposed to enhance transparency and reduce ambiguity in policymaking. These include^44,45:

• • Establishing clear policies that mandate disclosure of performance metrics, costs, and outcomes.

• • Ensuring public access to data through digital platforms.

• • Strengthening accountability via standardized reporting and whistleblower protections.

Additional measures involve^44-46:

• • Developing robust, standardized guidelines for information dissemination—such as requirements for clinical trial registration and conflict-of-interest management.

• • Implementing frameworks that clarify recommendations through iterative review processes that specify actions and conditions.

It is reported that political crises and sanctions weaken budgets, restrict technology access, and limit international collaboration. ²⁵ The sanctions imposed on Iran’s healthcare system have contributed to deteriorating public health outcomes, increased catastrophic health expenditures, widening income inequality and poverty, and broader equity gaps. These measures have also strained the public health infrastructure and restricted opportunities for international collaboration and research.^47-49 Domestically, severe institutional inefficiency, inter-agency miscoordination, and weak DEO authority prevail.^11,19 Task dispersion, complex hierarchies, parallel structures, and lack of enforcement mechanisms cause agencies to neglect duties, sometimes leading to blatant violations like superficial vehicle inspections. ²⁶ The law thus lacks a clear, integrated, and capable governance architecture, which has led to an environmental policy failure.

It is reported that CAA lacks adequate performance metrics and enforcement guarantees. Ambiguities in terms such as “serious risk” and absence of quantitative agency evaluation indicators result in non-accountability, with routine performance presented as legal compliance. Penalties are non-deterrent, and revenue generation can create conflicts of interest.^20,22,23 Hence, effective incentive and punitive mechanisms are absent. In this regard, the exiting literature has documented the absence of clear metrics in several Iranian laws and policies, notably Iran’s General Health Policies (IGHP) and Health Transformation Plan (HTP), where targets remain undefined, supporting data are inadequate, and mechanisms for tracking progress are lacking. Health information laws are constrained, often derived from provisions in unrelated domains, and lack standalone metrics for confidentiality, privacy, or disclosure, thereby engendering interpretive ambiguities. Additionally, these frameworks exhibit unstable directives, suboptimal monitoring precision, and opaque guidelines devoid of consistent evaluative metrics.^50-55

Despite challenges, the law shows progress: increased public awareness, attention to air standards, staged emission standards, expansion of vehicle inspection duties citywide, Ministry of Interior’s obligation to enhance public transport, vehicle fleet modernization, fuel standardization, renewable energy development, improved waste management and energy/material recovery, restrictions on excessive electromagnetic emissions, urban green belts, ¹⁰ national dust alert network, desertification control, economic instruments for pollution control, and regional cooperation on dust prevention.^{10,22,23,25,56} These represent improvements over previous policies. Nevertheless, design flaws and weak implementation prevent optimal execution of legal duties, leaving serious gaps in pollution reduction.^10-12

Limitations and Policy Implications

This study acknowledges a methodological limitation: it was confined to a review of existing literature, without incorporating expert opinions due to constraints on resources. Future research could extend this foundation by integrating contextual expert perspectives to yield a more comprehensive understanding of the subject. Nevertheless, the present study offers several significant implications for policymakers, administrators, and other stakeholders in Iran as well as comparable contexts in other countries. Accordingly, the following policy recommendations are presented (Figure 2):

• • Mobilize political commitment: Effective air pollution control requires sustained political will, as economic pressures and short-term priorities often marginalize environmental issues. Achieving change demands public discourse, pressure from scientific elites, civil society engagement, and evidence on health impacts. Universities, scientific associations, NGOs, and health advocates play key roles.

• • Develop evidence-based policy studies: Current law lacks sufficient evidence. Continuous collaboration between legislative/executive bodies and academia is essential to generate precise quantitative studies, including emission inventories, pollutant shares, sources, regular air quality assessment, and monitoring of policy outcomes. ³ Transparent data infrastructure must be accessible to the public, researchers, and agencies, shifting from “intuition-based” to evidence-based policy.

• • Comprehensive revision of the Clean Air Act: The current law is fragmented, ambiguous, and lacks a systemic approach. A full revision is needed to clarify and make agency duties measurable, define performance indicators, remove conflicting or ineffective provisions, and incorporate international best practices.

• • Reform and strengthen governance: Due to widespread miscoordination and institutional weaknesses, an integrated, multi-sectoral governance system is needed. Proposals include upgrading the DOE to a ministry with sufficient authority, resources, and capacity, or establishing a cross-sectoral national air pollution agency.^27,28 Regardless of its form, governance design must ensure adequate power, resources, and enforcement mechanisms, institutional integration, binding agency obligations, and transparent oversight and accountability.

• • Secure sustainable financing: Law implementation requires stable funding. Mechanisms include dedicated revenue sources (green taxes, targeted pollution levies), market-based private sector participation, environmental budget chapters with defined pollution-reduction programs, and cost–benefit models for pollution control projects. ³⁰

• • Legally mandate use of fines for pollution reduction: Environmental fines currently enter the general treasury and may be misallocated. All air pollution fines should be stored in a dedicated environmental fund, used only for monitoring, fleet renewal, fuel quality improvement, clean energy development, and green industry support, with annual public transparency reports to prevent conflicts of interest and enhance policy effectiveness.

• • Strengthen international and regional cooperation: Given transboundary pollutants, sanctions, and technology limitations, international collaboration is essential. Actions include regional dust management programs, leveraging global monitoring and modeling capacities, technology transfer, and active environmental diplomacy for clean technology access. ¹⁰

• • Enhance enforcement and legal deterrence: Penalties must correspond to environmental harm and be deterrent. Criminal and administrative accountability systems should be efficient, agency non-compliance prosecutable and publicly disclosed, and the judiciary actively engaged in law enforcement. ²⁶

• • Develop renewable energy: Fossil fuel use in industry and power plants is a major pollution source. Key measures include supporting solar and wind power plants, facilitating private investment, energy subsidy reforms to reflect real fuel costs, and industrial modernization with energy efficiency improvements.

• • Design integrated data governance and monitoring system: A comprehensive framework for environmental and air pollution data governance is essential, specifying mandatory data and equipment quality standards, clarifying inter-agency responsibilities, and establishing a technology roadmap for intelligent systems, modeling, and continuous monitoring to avoid duplication, task conflicts, and data fragmentation.

• • Ensure data and performance transparency: Transparency is central to effective governance. Key actions include publicly releasing analyzable pollution monitoring data, reporting government revenue from environmental fines and expenditures for environmental objectives, annual progress reporting to citizens, parliament, and media, and dashboards showing agency performance. ²²

• • Promote public participation and accountability mechanisms: Active citizen participation can pressure agencies and enhance transparency. Measures include citizen reporting platforms, publicly accessible and understandable monitoring data, and agency accountability systems responding to complaints and reports, strengthening public trust and policy sustainability.Figure 2

Figure 2.

Screening flowchart

Conclusion

This study aimed to identify, categorize, and systematically analyze the challenges and deficiencies inherent in the CAA and its implementation in Iran. The study indicated that the main challenge of the CAA lies not in its existence but in its design, governance, financing, and supporting infrastructure. In this regard, governance and institutional challenges constituted the predominant proportion of factors impeding the policy implementation. Effective implementation requires a fundamental revision of governance architecture, creation of sustainable financial models, strengthening the independence and authority of the DOE, reliance on scientific evidence, data transparency, and redesign of public participation mechanisms. Without structural and institutional reforms, even the best laws cannot effect change. Therefore, a comprehensive legal revision alongside genuine political commitment to air pollution control is essential; otherwise, current pollution trends and associated health impacts are likely to persist. Future research is warranted to furnish additional insights into this topic within the extant literature.

Ethical Considerations

The authors affirm that this study was conducted in full accordance with ethical principles of research integrity and reporting. An ethical clearance with code IR.SSU.SPH.REC.1404.114 has been obtained from the Shahid Sadoughi University of Medical Sciences.

Data Availability Statement

The research data is available upon request from the corresponding authors of the manuscript.*