Impact of lockdown associated with COVID19 on air quality and emissions from transportation sector: case study in selected Indian metropolitan cities

This study examines the impact of air quality in selected Indian metropolitan cities during the COVID19 pandemic lockdown period. Concentrations of air quality parameters such as PM(2.5), NO(2), SO(2), and CO during the transition to lockdown and the actual lockdown period were compared with business as usual periods (a period prior to COVID19 lockdown and a corresponding period in 2019) to estimate the reduction in emission in four major IT hubs in India namely Bengaluru, Chennai, Hyderabad and Pune. A 40–45% reduction in PM(2.5) concentration was observed, in these cities, during the lockdown compared to the corresponding period in 2019 and a 20–45% reduction was observed compared to business as usual period in 2020. A vehicle kilometer traveled (VKT)-related questionnaire survey-based study in Hyderabad revealed that, with 48% of population utilizing work-from-home during the transition to lockdown period, vehicular PM(2.5) emission in Hyderabad reduced by 54% compared to usual traffic emissions prior to COVID19 lockdown. Furthermore, it was estimated that emission of up to 3243, 777, 113, and 54 tons/year of CO, NOx, PM(2.5), and SO(2), respectively, could be avoided in Hyderabad alone, if work-from-home is implemented on a 2 days/week basis. The experience from this study can be used to develop policies favoring reduced use of private vehicles or implementation of work-from-home to combat air pollution and reduce carbon emissions.