Bangladesh’s capital Dhaka ranked second among cities with worst quality in the Air Quality Index (AQI) on Thursday morning.

It had an AQI score of 164 at 8:08am. The air was classified as ‘unhealthy’.

Mongolia’s Ulaanbaatar and Nepal’s Kathmandu occupied the first and third positions with AQI scores of 218 and 161 respectively.

When the AQI value is between 151 and 200, every city dweller may begin to experience adverse effects in their health, particularly members of sensitive groups.

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. The air quality usually improves during monsoon.