Photo: Mehedi Hasan/Dhaka Tribune

Delhi, Chengdu and Kolkata occupied the next three slots

Dhaka, capital city of Bangladesh, has once again ranked worst in the Air Quality Index (AQI).

Dhaka received a score of 194 at 09:20am on Sunday, indicating that the air quality was unhealthy, reports UNB.

In the index, Delhi of India, Chengdu of China and Kolkata of India occupied the next three slots with a score of 182, 174 and 173, respectively.

When the AQI value is between 151 and 200, every city dweller may begin to experience adverse effects in their health, particularly members of sensitive groups.

The air quality is categorized as good when the AQI score remains between 0 and 50 while the air is moderate when score is from 51 to 100. When the number is between 101 and 150, the air is classified as unhealthy for sensitive groups.

The AQI, an index for reporting daily air quality, tells people how clean or polluted the air of a certain city is, and what associated health effects might be a concern for them.

Bangladesh's overcrowded capital has been grappling with air pollution for a long time. The air quality generally worsens during summer and shows signs of improvement during monsoon.