Air Quality in the New Delhi Metropolis under COVID-19 Lockdown

TL;DR

This study examines the impact of COVID-19 lockdown measures on air quality in New Delhi, showing significant reductions in major pollutants through satellite and ground data analysis, informing future pollution control strategies.

Contribution

It provides a comprehensive analysis of satellite and ground-based data to quantify air quality improvements during COVID-19 lockdown in New Delhi, highlighting the effects of reduced human activity.

Findings

50% reduction in PM2.5 levels

71.9% reduction in NO2 levels

88% reduction in CO levels

Abstract

Air pollution has been on continuous rise with increase in industrialization in metropolitan cities of the world. Several measures including strict climate laws and reduction in the number of vehicles were implemented by several nations. The COVID-19 pandemic provided a great opportunity to understand the daily human activities effect on air pollution. Majority nations restricted industrial activities and vehicular traffic to a large extent as a measure to restrict COVID-19 spread. In this paper, we analyzed the impact of such COVID19-induced lockdown on the air quality of the city of New Delhi, India. We analyzed the average concentration of common gaseous pollutants viz. sulfur dioxide (SO$_2$), ozone (O$_3$), nitrogen dioxide (NO$_2$), and carbon monoxide (CO). These concentrations were obtained from the tropospheric column of Sentinel-5P (an earth observation satellite of European Space Agency) data. We observed that the city observed a significant drop in the level of atmospheric pollutant's concentration for all the major pollutants as a result of strict lockdown measures. Such findings are also validated with pollutant data obtained from ground-based monitoring stations. We observed that near-surface pollutant concentration dropped significantly by 50% for PM$_{2.5}$, 71.9% for NO$_2$, and 88% for CO, after the lockdown period. Such studies would pave the path for implementing future air pollution control measures by environmentalists.