Shawdesh Desk: Bangladesh’s capital Dhaka ranked fourth worst in the Air Quality Index (AQI) on Wednesday morning.

The overpopulated megacity’s air quality was classified as unhealthy as it had an AQI score of 185 at 11:31am.

Pakistan’s Karachi, India’s Kolkata, Nepal’s Kathmandu occupied the top three positions in the list with scores of 206, 198 and 195 respectively.
When the AQI score is between 151 and 200, every city dweller may begin to experience health effects. In this situation, people with respiratory diseases are advised to avoid prolonged outdoor exertions.

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.

Bangladesh’s overcrowded capital has been grappling with air pollution for a long time. The quality usually improves during monsoon.