Effect of COVID-19 lockdown on heavy metal contamination in Yamuna river water of Delhi region

An unprecedented twenty-one-day nationwide lockdown was imposed on March 24, 2020, at midnight by the Government of India as a preventive approach to contain the COVID-19 spread, which was further
extended up to May 31, 2020, in three more phases. The total lockdown led to the complete closure of the industries, thus ceasing the economic activities in the nation. This hindered the speed of the flow of
resources used in the production process and the goods produced, and the waste discharged into the environment. As a result, industrial effluents are reduced, and measurable data support the clearing of
pollutants from the atmosphere, soil, and water compartments (Invest India 2020). Amidst the global gloom of COVID-19 causing severe damage to health, the economy, and general societal well-being, the
lockdown has provided a unique opportunity to monitor the baseline pollution levels in several environmental matrices, particularly in the cities facing severe anthropogenic pollution issues.