Urban air pollution reduction: evidence from phase-wise analysis of COVID-19 pandemic lockdown

Until 31 May 2020, more than six million confirm COVID-19 cases had been reported worldwide. Lockdown has resulted in significant air quality improvement, especially urban regions. The lockdown acted as a natural experiment empowering researchers, policymakers, and governing bodies. present study focuses on quantifying analysing the effect of India’s metropolitan cities, namely New Delhi, Mumbai, Kolkata, Chennai, Bangalore. analyses phase-wise diurnal variations from 24 March 2020 to while focussing on-peak off-peak duration concentrations. To investigate reason behind pollutant reduction, correlation drop percentages concentrations with vehicle population, extent construction activity, meteorological parameters are analysed. 24-h PM10 PM2.5 showed high (R2 = 0.97 0.72, respectively) city’s population. During peak hours, inland cities (Delhi Bangalore), extensive fleet, recorded higher coastal (Mumbai, Kolkata). With respect 2019 concentration, maximum decrease averaged across five locations was NO2 (46%), followed by (40%), (37%), CO (19%). SO2 O3 contrarily an overall increase 40% 41%. These results wherein vehicular pollutants indicate that reduced traffic primarily influenced improvement during lockdown.