Lockdown cut NO2 levels by over 70% in Delhi, says UN

Levels of nitrogen dioxide fell by more than 70 per cent during the lockdown in New Delhi, a UN policy brief said on Tuesday, warning that the environmental gains could be temporary if the cities reopen without policies to prevent air pollution and promote de-carbonisation.

The UN Secretary-General's Policy Brief on 'COVID-19 in an Urban World' said that with an estimated 90 per cent of all reported COVID-19 cases, urban areas have become the epicentre of the pandemic. It also pointed out that several new scientific studies suggest that poor air quality is correlated with higher COVID-19 mortality rates.

The size of their populations and their high level of global and local interconnectivity make them particularly vulnerable to the spread of the virus.

The brief said that while pollution and greenhouse gas emissions have fallen sharply during the pandemic when countries halted their economies to contain the spread of the virus, these environmental gains are expected to be temporary if economies reopen without policies in place that prevent air pollution and promote decarbonisation.

"Levels of nitrogen dioxide fell by more than 70 per cent during the lockdown in New Delhi (India), 40 per cent in urban areas in China, 20 per cent in Belgium and Germany, and 19-40 per cent in different areas of the US," the brief said. A nincrease in fine particulate matter has been associated with an 8 per cent increase and up to 21.4 per cent increase in deaths.