COVID-19 Lockdown: Impact on Air Quality of Three Metro Cities in India

Abstract

Covid-19 health pandemic resulted in nationwide lockdown in India. With the closure of almost everything from educational institutions to industries less no of vehicles came out on roads. As the vehicular emission is one of the reasons of higher rate of pollution in metro cities so this step of lockdown has shown positive impact on environment with decrease in pollution level. Despite various attempts made by the government over the last few years nothing proved fruitful but this forced decision has shown some great results. We have analysed the changes in the quality of air during lockdown period from 25th March to 30th April, 2020 over pre-lockdown period from 1st March to 24th March, 2020 of Delhi, Mumbai and Kolkata which are the polluted cities of India. Seven air pollutants PM2.5, PM10, O3, CO, SO2, NH3, and NO2 have been used to calculate Air Quality Index (AQI) to see the changes in quality of air. The results showed that due to lockdown concentration of various pollutants PM2.5, PM10 and NO2 has decreased significantly. There is a heavy reduction of 42.27%, 69.28% and 74.80% in concentration of NO2 in Delhi, Mumbai and Kolkata respectively. It has been deduced from change in AQI values that there is a significant improvement in quality of air during lockdown in Delhi, Mumbai and Kolkata.