Comparative study on air quality status in Golden Quadrilateral cities before and during the COVID-19 lock down period.

The COVID-19 pandemics have affected every aspect of the human race and world economy. disease has been contaminated in almost part India. A threat for poor standards induced premature mortality from cardiovascular respiratory diseases. Amongst huge-reaching implications continuing outbreak, a significant enhancement air quality was detected all around globe after lockdowns enforced several cities lockdown influenced environment’s pollution level improved quickly due to very few activities. present work scientifically analyses pollutants (PM2.5, PM10, NO2, SO2) with meteorological parameters golden quadrilateral cities. purpose this paper is review analysis (Delhi, Kolkata, Chennai, Mumbai). Data are collectively taken different locations regions Delhi, Mumbai before during compared data both periods. Comparison pre-lockdown 2019 respect 2020 respectively show huge reduction amounts pollutants. Our objective find implication measures on levels particularly investigation focused PM2.5, SO2 which directly transmitted by action formed through chemical reaction atmosphere as well quantify short-range long-range health impact.