Dhaka ranked fourth among the world’s most polluted cities on Wednesday morning, recording an Air Quality Index (AQI) of 148 at 08:52 am.

The air quality was classified as ‘unhealthy for sensitive groups’, indicating increased health risks for vulnerable populations, particularly children, the elderly, pregnant individuals, and those with heart or lung conditions, according to the AQI scale.

Lahore in Pakistan, Delhi in India and Karachi in Pakistan occupied the top three spots, with AQI scores of 193, 159 and 154 respectively.

According to AQI standards, a reading between 101 and 150 is considered ‘unhealthy for sensitive groups’, 151 to 200 ‘unhealthy’, 201 to 300 ‘very unhealthy’, while levels above 301 are deemed ‘hazardous’, posing serious health risks.

The AQI, which provides daily updates on air quality, indicates how clean or polluted the air is and highlights potential health impacts.

In Bangladesh, the AQI is calculated based on five major pollutants: particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and ozone.

Dhaka has long struggled with air pollution, with air quality typically worsening in winter and improving during the monsoon season.

The World Health Organization estimates that air pollution causes around seven million deaths globally each year, mainly due to stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.