Assessment of Air Quality Index in major cities of India - Lessons from Lockdown

Abstract

An unexpected closure episode of most of the public movement and industrial activities during the initial spreading duration of COVID-19 has significantly resulted in drastic reduction of environmental pollution in the urban areas globally. Being an active bio-aerosol with pandemic effect, COVID-19 presents a never-before scenario for the meteorologists and environmental engineers to look for systematic analysis of the overlap of air quality modelling with modifications in the atmospheric science. The long-term monitoring of pollution records help in defining unique indices for categorizing the severity of the existing pollution and thus helps in developing strategies for improving environmental quality. In this study, we present the observations in major air quality parameters in selected major cities of India using air quality index (AQI) before and after the announcement of a nationwide lockdown that extended nearly for many months. The results indicate a major sustaining type of decline in the average AQI values for major Type-1 and Type-2 cities due to the reduction in public movement and industrial activities, whereas the reduction AQI values for Type-3 and Type-4 cities were observed to be fluctuating due to the continued small-scale industrial activities and low level of awareness about ban on public gathering programmes.