COVID 19 Lockdown - Air Quality Reflections in Indian Cities

ABSTRACT 

The emergence of COVID-19 put pressure on the Governments of most of the countries in the world to enforce nationwide lockdown (restriction of all non-essential activities) to curtail the spread of infection. The nationwide lockdown created an adverse impact on the economies around the world and altered the day-to-day life of people. The restrictions on pollution generating activities during the lockdown period resulted in an overall improvement of the air quality throughout the world including India. This study evaluated the impact on air quality in 46 cities throughout India and the findings indicate that on average, PM_2.5 and NO_x, concentrations reduced by about 34% and 60%, respectively at different locations in India. PM_2.5 concentrations reduced by about 23%, 16%, 32%, and 28% in small, medium, large and megacities, respectively. However, the reduction in NO_x concentrations was dissimilar to PM_2.5 in these cities. The findings further suggested that the impact of lockdown on air quality was not homogenous across the country and was probably due to varying background contributions. The average concentrations of PM_2.5 and NO_x at background stations were found higher in large and mega cities than the smaller cities. The PM_2.5 concentrations at background stations were higher in North India in comparison to other parts of India.