Delhi's air pollution drops by 49% owing to coronavirus-induced lockdown

Skies in the national capital have been showing an unprecedented -- yet fantastic -- side-effect amid the nationwide coronavirus-enforced lockdown. They have turned blue and, perhaps, breathable.

The nationwide lockdown has enforced restrictions and self-quarantine measures, which reduced emissions from transportation and industries. To this end, the latest air quality index (AQI) says Delhi has shown 49 per cent reduction in pollution.

The capital city has witnessed 87.9 per cent decline in nitrogen oxide, whose main contributor is transport. Due to the lockdown, a study conducted by the Indian Institute of Technology (IIT) Delhi stated, "Delhi observed the maximum reduction of 49 per cent in AQI. This reduction in AQI was also associated with a change in dominant pollutants in many cities."

AQI captures various air pollutants, such as particulate matter (PM), nitrogen oxide, sulphur dioxide, ozone, carbon monoxide and so on.

According to the study, the country has witnessed 43, 31, 10, and 18 per cent decreases in PM 2.5, PM 10, CO, and NO2 levels during the lockdown period compared to previous years. 

In Delhi, the country's most polluted city, transport contributes 41 per cent to pollution, industry 18.61 per cent, power 4.92 per cent and residential emissions 2.96 per cent.

A slight increase in sulphur dioxide concentrations was, however, observed during this period compared to the previous year. Ozone also increased by 10 per cent as compared to the last three years.

Additionally, according to the Central government's System of Air Quality and Weather Forecasting and Research, all sources of pollution have decreased during the lockdown, other than bio-fuel emissions.

Also, India's carbon dioxide emissions have also fallen for the first time in four decades, according to a study by the Centre for Research on Energy and Clean Air (CREA).