Bangladesh’s capital Dhaka was ranked third worst in Air Quality Index (AQI) on Monday morning.

It had an AQI score of 233 around 8:20am. The air was classified as ‘very unhealthy’.

When the AQI score is between 201 and 300, everyone may experience more serious health effects, the UNB reported.

India’s Delhi and Mongolia’s Ulaanbaatar occupied the top two positions in the list of cities with worst air with scores of 317 and 272 respectively.

When the AQI score is more than 300, the air quality is considered hazardous and everyone may experience more serious health effects.

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, the overcrowded megacity, has long been grappling with air pollution. The air quality usually improves during monsoon.