Dhaka: Dhaka ranked second among the world’s most polluted cities on Friday morning, recording an Air Quality Index (AQI) score of 251 at 9:10 am. The city’s air quality was classified as ‘very unhealthy’, posing a serious health risk, according to the AQI report.

According to United News of Bangladesh, Bosnia and Herzegovina’s Sarajevo topped the list with an AQI score of 404, while India’s Delhi ranked third with an AQI score of 192. The AQI scale categorizes air quality with scores between 50 and 100 as ‘moderate’, 101-150 as ‘unhealthy for sensitive groups’, 151-200 as ‘unhealthy’, 201-300 as ‘very unhealthy’, and readings above 301 as ‘hazardous’, posing severe health risks.

The AQI, which measures daily air quality, indicates how clean or polluted the air is and highlights potential health effects. In Bangladesh, the index is calculated based on five pollutants: particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulphur dioxide (SO2), and ozone.

Dhaka has long been grappling with air pollution, which typically worsens during the winter and improves during the monsoon season. The World Health Organization (WHO) 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.