Dhaka, Jan. 15 -- Dhaka, the densely populated capital of Bangladesh, ranked fisrt among the world's most polluted cities on Thursday morning, recording an Air Quality Index (AQI) of 271 at 9:13 am.

Today, the city's air was classified as 'very unhealthy', indicating a serious health threat, according to the AQI report.

Bishkek in Kyrgyzstan, Karachi in Pakistan, and Kolkata in India occupied the second, third, and fourth spots on the list, with AQI scores of 215, 208, and 200 respectively.

According to the AQI scale, a reading between 50 and 100 is considered 'moderate', with generally acceptable air quality, though sensitive individuals should limit prolonged outdoor exertion. AQI levels of 101-150 are 'unhealthy for sensitive groups...