Positive impact of COVID-19 induced lockdown on the environment of India's national capital, Delhi

The rapid emergence of novel coronavirus disease has shown some positive impact on the health of natural environment. Present study was aimed to assess the impact of COVID-19 induced lockdown on the water quality of Yamuna River and air quality of national capital territory, Delhi. Significant decline in air quality pollutants like NH3, SO2, CO, PM2.5, NO2 were observed. The major decline was found in the levels of PM2.5, SO2, NO2 and NH3. The less significant decline was seen in the CO level during the lockdown period. Furthermore, the overall decline in the concentrations of BOD, COD and increase in pH suggesting an improvement in Yamuna water during the lockdown. However, the concentration of DO was found insignificant during the lockdown period. Additionally, comparative analysis of morbidity, mortality as well causalities during this period has also been recorded to establish correlation of pre and post COVID-19 situations. Altogether, present study is found to be a useful supplement for policymakers because marked improvements in the water and air quality indices have been observed after enforcement of lockdown leading to control of the various pollution sources. Therefore, periodical lockdown can be utilized as an effective mitigation measures for natures' restoration.