The residents of Bangladesh's capital Dhaka are at health risk as the megacity ranked top among cities with worst air quality on Monday morning.
It had an AQI score of 306 at 08:10am. The air was classified as 'hazardous' and in this condition, everyone may experience more serious health effects.
When the AQI value is more than 300, people are advised to avoid all outdoor exertion.
Kyrgyzstan's Bishkek and Pakistan's Lahore occupied the second and third spots in the list of cities with the worst air quality with AQI scores of 227 and 215 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).
The Department of Environment has also set national ambient air quality standards for these pollutants. These standards aim to protect against adverse human health impacts.
Dhaka has long been grappling with air pollution. Its air quality usually improves during monsoon.