Dhaka ranked 27th among the world's most polluted cities on Friday morning, recording an Air Quality Index (AQI) score of 84 at 11:06am. 

According to the AQI scale, the city's air quality was classified as “moderate”, meaning the air is generally acceptable for most people, although a very small number of unusually sensitive individuals may experience moderate health concerns.

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Chicago, Detroit and New York of the United States grabbed the top three spots on the global pollution list with an AQI score of 651, 462 and 203, respectively.

According to AQI standards, a reading between 101 and 150 is considered “unhealthy for sensitive groups”, 151 to 200 “unhealthy”, 201 to 300 “very unhealthy”, while levels above 301 are deemed “hazardous”, posing serious health risks.

The AQI, which provides daily updates on air quality, indicates how clean or polluted the air is and highlights 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.