Dhaka ranked fourth among the world’s most polluted cities on Wednesday morning, recording an Air Quality Index (AQI) score of 134 at 8:35 am.

According to the AQI scale, the capital’s air quality was classified as “unhealthy for sensitive groups,” meaning that while the general public is unlikely to be affected, children, older adults and people with respiratory or heart conditions may face health risks if exposed for prolonged periods.

Uganda’s Kampala topped the list with an AQI score of 173, followed by Indonesia’s Jakarta at 164 and the Democratic Republic of Congo’s Kinshasa at 148.

An AQI score between 101 and 150 is considered “unhealthy for sensitive groups,” while readings between 151 and 200 are classified as “unhealthy.” Scores ranging from 201 to 300 are deemed “very unhealthy,” and readings above 301 are considered “hazardous,” posing serious health risks.

The AQI serves as a daily measure of air quality, indicating how clean or polluted the air is and the potential health effects associated with exposure.

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 generally worsens during the winter months and improves during the monsoon season.

According to the World Health Organization, air pollution is responsible for around seven million deaths globally each year, primarily due to stroke, heart disease, chronic respiratory diseases, lung cancer and acute respiratory infections.