Dhaka, the densely populated capital of Bangladesh, ranked 12th among the world’s most polluted cities on Monday morning, recording an Air Quality Index (AQI) score of 83 at 8:40am.

According to the AQI index, Dhaka’s air quality was classified as ‘moderate’, posing a slight health risk.

Pakistan’s Lahore, India’s Delhi and Nepal’s Kathmandu topped the list of the world’s most polluted cities, with AQI scores of 188, 173 and 154 respectively.

An AQI between 101 and 150 is considered ‘unhealthy for sensitive groups’, while a score between 151 and 200 is classified as ‘unhealthy’. Readings between 201 and 300 are termed ‘very unhealthy’, and anything above 301 is regarded as ‘hazardous’, posing serious health risks.

The AQI measures daily air quality, indicating how clean or polluted the air is and the possible health effects on people.

In Bangladesh, the AQI is calculated based on five major pollutants — particulate matter (PM10 and PM2.5), nitrogen dioxide, carbon monoxide, sulphur dioxide and ozone.

Dhaka has long struggled with severe air pollution. Air quality usually worsens during winter and improves with the arrival of the monsoon season.

According to the World Health Organization (WHO), air pollution causes around seven million deaths globally each year, mainly from stroke, heart disease, chronic respiratory diseases, lung cancer and acute respiratory infections.