The capital of Bangladesh, Dhaka, was ranked second worst city in the Air Quality Index (AQI) on Sunday.
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.
Dhaka had a score of 208 at 8:47pm this morning, indicating that the air quality was very unhealthy.
A numerical value between 151 and 200 indicates that everyone may begin to experience health effects. Members of sensitive groups may experience more serious health effects.
Air quality between 201 and 300 is classified as 'very unhealthy'. If the score is between 301 and 500, it is classified as 'hazardous'.
Mongolia's Ulaanbaatar was on the top of the table with a score of 235.
Dhaka, one of the most densely populated cities in the world, has been grappling with air pollution for a long time.
The air quality generally worsens during summer and shows signs of improvement in monsoon when the dust settles.