It had an AQI score of 186 at 8am. The air was classified as ‘unhealthy’.  When the AQI score is between 151 and 200, everyone may begin to experience health effects while members of the sensitive groups may experience more serious health effects.

In this situation, experts recommend children, adults and people with respiratory diseases to limit outdoor exertion.

Australia’s Canberra, India’s Delhi and Pakistan’s Karachi occupied the top three positions in the list of cities with worst air with scores of 373, 241 and 234 respectively.

Also Read: Air Quality Index: Dhaka ranks 13th worst

When the AQI score is between 201 and 300, every city dweller is likely to be affected.

But when the value 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.