Bangladesh’s capital Dhaka ranked third among cities with the worst air quality on Wednesday morning.

It had an AQI score of 270 at 08:52 am. The air was classified as ‘very unhealthy’.

Mongolia’s Ulaanbaatar and India’s Delhi occupied the first and second spots in the list of cities with the worst air quality with AQI scores of 313 and 297 respectively.

When the AQI value is between 201 and 300, the entire population is more likely to be affected. In this situation, children are advised to limit outdoor activities.

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.