Dhaka, the capital of Bangladesh, briefly emerged as the world’s most polluted city on Wednesday, with a “hazardous” index level of 325, according to Swiss climate monitor IQAir.

The main causes of the poor air quality in Dhaka are the burning of fossil fuels, brick kilns, construction dust, and agricultural waste. The toxic smog poses serious health risks for the residents, especially those with respiratory and cardiovascular diseases.

Other South Asian cities, such as Delhi, Lahore, and Kathmandu, are also suffering from severe air pollution. The situation calls for urgent action from the governments and the public to reduce emissions, promote renewable energy, and improve environmental regulations.