Dhaka ranked fifth among the world's most polluted cities on Wednesday morning, recording an Air Quality Index (AQI) score of 175 at 10:20am.
The city's air quality was classified as “unhealthy”, indicating that pollution levels could pose health risks to the general population.
Singapore ranked first with an AQI score of 194, followed by Delhi, India, with 180. Kuala Lumpur, Malaysia, ranked third with a score of 177.
According to the AQI scale, readings between 101 and 150 are classified as “unhealthy for sensitive groups”, while scores between 151 and 200 indicate “unhealthy” air. Readings between 201 and 300 are considered “very unhealthy”, while scores above 300 are classified as “hazardous” and indicate serious health risks.
The AQI provides daily information on how clean or polluted the air is and the potential health effects of exposure.
In Bangladesh, the AQI is calculated using five major pollutants: particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), sulphur dioxide (SO2) and ozone.
Dhaka has long struggled with air pollution. Air quality typically deteriorates during winter and improves during the monsoon season.
The World Health Organization estimates that air pollution causes around seven million deaths worldwide each year. The associated health effects include stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.