A study during lockdown period based on AQI over Indian mega cities during COVID-19

ABSTRACT

The COVID-19, the most deadly challenge human being could have imagined, has become a reality now and the whole world is passing through the worst pandemic situation. From the challenges of invention of life saving vaccine or medicine to keeping economy at right track are the most talked about hurdles in front of all of us. But if we look at the other side of the coin, the blessings that came in form of disguise could be realised. The paper emphasizes on those aspects during lockdown that was imposed in India for three weeks initially that is 24th March to 14th April 2020 and later on till 3rd of May 2020. As a result of this forced restrictions, pollution level in whole India, specially in metro or mega cities where large population and pollution is a deadly combination, drastically changed. For analysing air quality, the metro-cities like Delhi, Kolkata, Chennai and Mumbai has been investigated here. The pollutant parameters PM 2.5, SO2, NO2, along with CO, O3 and overall AQI (Air Quality index) has been collected and comparative study was done before and after lockdown and even for the year 2018 and 2019 too. Reduction of level of pollutants in significant amount of percentage is observed for all the metro cities where variation of reduction level from city to city is also significant. The effectiveness of lockdown over different metro cities are also very significant, pointing towards alertness of local people and population concentration. Finally, the study can be used in future as case study for controlling pollution with controlled lockdown and this can be practiced in future once or twice yearly to save our motherland. © 2021 Institute of Physics Publishing. All rights reserved.