The changes in the air quality of Wazirpur, Delhi due to the COVID-19 shutdown

The Corona Virus Disease (COVID)-19 pandemic led to the death of countless lives worldwide, which forced most countries and cities to impose a shutdown, bringing a halt to major human activities. While this shutdown caused a significant economic crisis, resulting in loss of livelihood to many people, it caused relief to the environment. Delhi in India is amongst the highest air-contaminated cities worldwide, and the COVID-19 shutdown helped improve air quality. This paper studied the variation in air quality for Wazirpur, Delhi, during shutdown in 2020 and a similar time-period in 2019. The data was acquired from the Central Pollution Control Board (CPCB) open-access portal for six air contaminants viz. Carbon-monoxide (CO), Nitrogen-dioxide (NO(2)), Ozone (O(3)), Particulate Matter (PM(10) and PM(2.5)), and Sulphur-dioxide (SO(2)). Inferential statistical analysis was done to determine the trend in air quality variation during the shutdown compared to the previous year. Mean, standard deviation, percentage difference, linear regression and correlation analysis were made, and variable reduction in most air contaminants was noted. It was noted that for most of our observed time, the concentration of NO(2), O(3), PM(10), PM(2.5) and SO(2) in 2020 is lower than in 2019, while the concentration of CO is greater in 2020 than the corresponding time in 2019. The maximum decline was observed for PM10 (70.5%) during phase-1, while the maximum increase was observed in CO (32.3%) during phase-1. As the shutdown restrictions were eased out, an increase in the air contaminants was also noted.