Table 3.

RDD estimation

	AQI
	(1)	(2)	(3)
Treat * Post	− 0.174***	− 0.112**	− 0.120**
	(0.031)	(0.057)	(0.057)
Wind speed	− 0.011	− 0.011	− 0.012
	(0.009)	(0.009)	(0.009)
Precipitation	− 0.013**	− 0.013**	− 0.013**
	(0.006)	(0.006)	(0.006)
Humidity	0.555***	0.539***	0.525***
	(0.141)	(0.142)	(0.143)
Temperature	0.048***	0.050***	0.050***
	(0.005)	(0.005)	(0.005)
Time trend	No	1st order	2nd order
Fixed effects	Yes	Yes	Yes
Constant	3.706***	3.678***	3.696***
	(0.116)	(0.118)	(0.120)
Observations	825	825	825
R2	0.590	0.591	0.591

This table reports the impact of the lockdown policy on air pollution within a small window of locked cities. Column (1) presents the result of Model (1) but focusing on observations within 7 days before and after the issues of intervention policies. Column (2) and (3) presents the results of RDD strategy by adding a linear or quadratic time trend separately. The dependent variable is $\mathit{AQI}$. The key independent variable is $Treat\ast Post$

Significance at 10%, 5%, and 1% levels was indicated by *, **, and ***, respectively