Dhaka ranked fourth among cities with the poorest air quality on Wednesday morning, recording an Air Quality Index (AQI) score of 165 at 9:30am.

According to the AQI scale, this level is classified as ‘unhealthy’ and poses a serious threat to public health, especially for people with respiratory conditions, the elderly, and children.

Pakistan’s Lahore topped the list with an AQI of 182, followed by Manama in Bahrain (172) and Kolkata in India (166).

The AQI, a global standard for measuring air pollution, categorizes air quality as follows: 0–50 is ‘good’, 51–100 is ‘moderate’, 101–150 is ‘unhealthy for sensitive groups’, 151–200 is ‘unhealthy’, 201–300 is ‘very unhealthy’, and 301 or above is considered ‘hazardous’.

Bangladesh’s AQI is calculated based on concentrations of five pollutants: particulate matter (PM10 and PM2.5), nitrogen dioxide (NO?), carbon monoxide (CO), sulfur dioxide (SO?), and ozone (O?).

Dhaka has been struggling with poor air quality for years. Conditions typically worsen in the dry winter months due to increased dust, vehicular emissions, and industrial activities, but tend to improve during the monsoon season when rainfall helps clear pollutants from the air.

The World Health Organization (WHO) estimates that air pollution causes around seven million premature deaths globally each year, mostly due to stroke, heart disease, lung cancer, chronic respiratory diseases, and infections.