The densely populated capital of Bangladesh has once again topped the list of world cities with the worst air quality.Dhaka's air quality index (AQI) score of 489 at 6.29 am, considered 'severe'.
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. And an AQI between 401 and 500 is said to be 'severe'.
Pakistan’s Karachi and India’s Kolkata occupied the second and third spots in the list of cities with the worst air quality, with AQI scores of 173 and 166, 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).
Dhaka has long been grappling with air pollution issues. Generally, the capital's air starts getting fresh when monsoon rains begin from mid-June.In 2021, the average daily AQI score was 261 in January, 231 in February and 211 in March, which hit the record high in the last five years.