Dhaka: Dhaka, the densely populated capital of Bangladesh, ranked second among the world’s most polluted cities on Wednesday morning, recording an Air Quality Index (AQI) of 296 at 9:40 am. Today, the city’s air was classified as ‘very unhealthy’, indicating a serious health threat, according to the AQI report.

According to United News of Bangladesh, Lahore in Pakistan, Delhi in India, and Kolkata in India occupied the first, third, and fourth spots on the list, with AQI scores of 324, 293, and 232 respectively. The AQI scale, which reports daily air quality, helps residents understand how clean or polluted the air is and highlights potential health effects. In Bangladesh, the AQI is calculated based on five key pollutants: particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and ozone.

A breakdown of the AQI scale shows that a reading between 50 and 100 is considered ‘moderate’, with generally acceptable air quality, though sensitive individuals should limit prolonged outdoor exertion. AQI levels of 101-150 are ‘unhealthy for sensitive groups’, 151-200 is ‘unhealthy’, 201-300 is ‘very unhealthy’, and readings above 301 are considered ‘hazardous’, posing severe health risks.

Dhaka has long struggled with air pollution, which typically worsens in winter and improves during the monsoon season. The World Health Organization (WHO) estimates that air pollution causes about seven million deaths worldwide each year, primarily from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections.