Table 1.

Air quality indices.

References	Year	Name of Index	Parameters included
(Ott & Hunt, 1976)	1976	Pollution Standard Index	PM10, NO2, O3, CO, and SO2
(Babcock & Nagda, 1972)	1972	Oak Ridge AQI	PM10, NO2, O3, CO, and SO2
(Murena, 2004)	2004	Air Pollution Index	PM10, NO2, O3, CO, and SO2
(USEPA, 2004)	1999	Air Quality Index	PM10, NO2, PM2.5, O3, CO, and SO2
(Sowlat et al., 2011)	2011	Fuzzy AQI	PM10, PM2.5, O3, SO2, NO2 and CO, benzene, toluene, ethylbenzene, xylene, and 1, 3-butadiene
(Kyrkilis et al., 2007)	2007	Aggregate AQI	PM10, NO2, O3, CO, and SO2
(van den Elshout et al., 2008)	2008	Common AQI	PM10, O3, NO2 (main) and CO, SO2(auxiliary)
(Bishoi et al., 2009)	2009	New AQI	PM10, NO2, PM2.5, O3, CO, and SO2
(Sicard et al., 2011)	2011	Aggregate Risk Index	PM10, NO2, PM2.5, O3, and SO2
(CPCB, 2014)	2014	National AQI	PM10, NO2, PM2.5, O3, CO, and SO2
(Chelani et al., 2002)	2002	Air Quality Index	RSPM, SO2, and NO2