Dhaka: Dhaka ranked 4th among the world’s most polluted cities on Thursday morning, recording an Air Quality Index (AQI) score of 147 at 9:50 am.

According to United News of Bangladesh, the AQI scale classified the city’s air quality as ‘Unhealthy for Sensitive Groups’. This poses health risks to children, older adults, and individuals with heart or lung diseases, while the general public remains mostly unaffected.

Portland in the USA topped the global pollution list with an AQI score of 168, followed by Kampala, Uganda, with 160, and Kinshasa, DR Congo, with 159. The AQI standards define a reading between 101 and 150 as ‘unhealthy for sensitive groups’, 151 to 200 as ‘unhealthy’, 201 to 300 as ‘very unhealthy’, and levels above 301 are labeled ‘hazardous’, posing serious health risks.

The AQI provides daily updates on air quality, indicating how clean or polluted the air is and highlighting potential health impacts. In Bangladesh, the AQI is calculated based on five major pollutants: particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and ozone.

Dhaka has long struggled with air pollution, with air quality typically worsening in winter and improving during the monsoon season. The World Health Organization 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.