Bangladesh’s capital Dhaka on Monday morning ranked the 6th worst polluted city in the world in the Air Quality Index (AQI).

The air in Dhaka was categorised as ‘unhealthy for sensitive groups’ in the morning and the megacity had an AQI score of 137 at 08:50am.

When the AQI remains in between 151 and 200, members of sensitive groups may experience health effects. The general public is not likely to be affected in this condition.

South Africa’s Johannesburg, Pakistan’s Lahore and Delhi’s India occupied the first three spots in the list of cities with the worst air quality with AQI scores of 183, 156 and 156 respectively.

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

In Bangladesh, the AQI is based on five criteria pollutants – Particulate Matter (PM10 and PM2.5), NO2, CO, SO2, and Ozone (O3).

Bangladesh has a subtropical monsoon climate characterized by wide seasonal variations in rainfall, high temperatures and humidity.

Dhaka’s air starts getting fresh when rainfalls begin from mid-June. The air remains mostly acceptable during monsoon season from June to October.