New Delhi became the world's most polluted capital for the third consecutive year in 2020, Reuters reports.

India is home to 35 of the world's 50 most polluted cities, according to IQAir, a Swiss group that measures air quality levels based on the concentration of harmful airborne particles known as PM2.5.

Findings are based on the country's average annual particulate matter PM2.5 of airborne particles less than 2.5 microns in diameter. Prolonged exposure to PM2.5 can lead to fatal diseases, including cancer and heart problems.

In 2020, the average annual concentration of PM2.5 per cubic meter of air in New Delhi was 84.1, the study said.

Air pollution was responsible for 54,000 premature deaths in New Delhi in 2020, according to a recent study by Greenpeace Southeast Asia Analysis and IQAir.

Despite an 11% decline in the average annual PM2.5 level due to nationwide COVID-19 restrictions imposed last year, India has become the third most polluted country in the world after Bangladesh and Pakistan.

Air pollution in India is still dangerously high, the report said.