COVID-19 and Climate Change: Determinants of Air Pollution in Six Metro Cities of India

This paper suggests a new approach towards measuring, modelling and analysing air pollution in the context of COVID-19 growth and control, climatic variables, and un-lockdown. The study is based on daily data from 25 March 2020 to 19 October 2020 on COVID-19 cases and air pollution in six metro cities in India. The paper constructs city-wise Air Pollution Indices (APIs) based on PM2.5, SO2, CO and NO2 constituents. It models the impact of the growth of COVID-19, lockdown/un-lockdown and three climatic factors determining air pollution, namely, temperature, wind speed and humidity. There are wide differences among the six metro cities, with Delhi being the poorest in terms of air pollution by considering four individual air pollutants. Another finding is that COVID-19 peaked on 18 September 2020, during the first wave. With the help of Generalised Method of Moments (GMM), the paper models and measures the impact of disease growth, disease control and climatic factors on city-wise API. In general, new cases reduced pollution. An unexpected finding is that recovery reduced pollution in 4 of 6 cities. This may be because those who recovered became more conscious or there was a lagged effect. Also, lockdown reduces and un-lockdown increases air pollution. Wind speed and humidity reduce air pollution and extreme temperatures increase air pollution.