The Indian capital, home to more than 20 million people, was followed by the Bangladesh capital of Dhaka and Kabul, capital of Afghanistan, according to the study by IQ AirVisual, a Swiss-based group that gathers air-quality data globally, and Greenpeace. PM2.5, or particles of 2.5 micrometers or less in diameter, is so dangerous because it lodges deep in the lungs. The World Health Organization sets a daily mean air quality guideline of 25 micrograms of PM2.5 per cubic metre of air. "In mainland China, in particular, this has led to significant improvements in year-on-year reductions in PM2.5 levels," the groups said in their joint study. India is home to 15 of the 20 most polluted cities in the world, they said.

Source: bd News24 March 05, 2019 12:56 UTC