Impact of COVID-19 Lockdown on Ambient Air Quality in the Southwest Coastal Urban Regions of India

The rapid growth of urban areas and population as well associated development over recent decades have been a major factor controlling ambient air quality the environment in Kerala (India). Being located at southwestern fringe Indian peninsula, is one regions that has significantly influenced by activities Ocean. present study focuses on effect COVID-19 lockdown (in 2021) selected coastal metropolitan Kerala. Although previous research studies reported improvement during period, this demonstrates potential onshore transport pollutants period. Data from monitoring stations State Pollution Control Board Thiruvananthapuram (TM), Kollam (KL), Kozhikode (KZ), Kannur (KN) are used for analysis. Temporal variation concentration pre-lockdown (PRLD), (LD), post-lockdown (PTLD) periods (i.e., 1 March to 31 July) 2021 examined assess measures National Air Quality Index (AQI). Results indicate significant decline levels subsequent areas. All evident AQI, an increase different including CO, SO2, NH3 LD period suggests contributions multiple sources due marine traffic transboundary transport.