Dhaka remains world's most polluted city

Dhaka once again has topped a list of cities with the worst air quality in the world, reports UNB.

On Friday, the capital city's air quality index (AQI) at 10:32am read 216, considered 'poor' that is 'very unhealthy'. Earlier, Dhaka ranked top in the list on Wednesday.

An AQI between 201 and 300 is considered 'poor', while a reading of 301 to 400 is said to be 'hazardous', posing serious health risks to city residents.

Hanoi, the capital of Vietnam, and Kabul in Afghanistan occupied the second and third places in the list of cities with the worst air quality, at AQI scores of 209 and 205, respectively.

AQI, an index for reporting daily air quality, is used by government agencies to inform people how clean or polluted the air of a certain city is, and what associated health effects might be a concern for them.

In Bangladesh, the overall AQI is based on five criteria pollutants - Particulate Matter (PM10 and PM2.5), NO2, CO, SO2, and Ozone (O3).

Bangladesh has a subtropical monsoon climate characterised by wide seasonal variations in rainfall, high temperatures and humidity.

Generally, Dhaka's air starts getting fresh when monsoon begins from mid-June. The air remains mostly acceptable from June to October.