Chennai, the capital of Indian state of Tamil Nadu, is the fourth urban agglomeration in the nation and is the 36th largest urban area by population in the world. It is located on the Coromandel Coast off the Bay of Bengal and is center for the cultural, economical, and educational activities of south India. Similar to all other studied sites, the air quality of site 4—Manali Village, Chennai also confirmed improvement in terms of reduction in pollutant level during the confinement period. The mean concentrations of PM2.5, PM10, NH3, and SO2 were reduced by 54%, 17%, 30%, and 39% respectively as shown in Fig. 4, while due to fuel and coal burning, vehicular emissions, and continuous functioning of power plants in the neighborhood of site 4, there was no significant reduction in NO2 (+ 1 μg/m3), CO (+ 9 μg/m3), and ozone levels (+ 29 μg/m3) (https://www.cag.org.in/blogs/air-quality-chennai-during-lockdown-do-we-have-clues-mitigate-air-pollution).