Bangladesh's capital Dhaka ranked 22nd among cities with the worst air quality on Sunday morning at 9:15 am, recording an Air Quality Index (AQI) score of 81.

India's capital, Delhi, topped the list with an AQI score of 195, making it the most polluted city in the world. Pakistan's Lahore ranked second with an AQI score of 187, while Santiago occupied the third position with a score of 165.

An AQI score between 51 and 100 is considered "moderate," indicating acceptable air quality, although some pollutants may pose a moderate health concern for a small number of unusually sensitive individuals.

An AQI reading between 101 and 150 is considered ‘unhealthy for sensitive groups’, while 151–200 is categorised as ‘unhealthy’. Readings between 201 and 300 are regarded as ‘very unhealthy’, and levels above 301 are considered ‘hazardous’, posing serious health risks to the population.

In Bangladesh, the AQI is calculated based on five major pollutants: particulate matter (PM2.5 and PM10), nitrogen dioxide (NO₂), carbon monoxide (CO), sulphur dioxide (SO₂), and ozone.

Dhaka frequently experiences deteriorating air quality, particularly during the dry winter months, while conditions generally improve during the monsoon season.

Experts say prolonged exposure to polluted air can cause respiratory illnesses, cardiovascular diseases and other health complications, particularly among children, older adults and people with existing health conditions.