DHAKA: The air quality in Dhaka continued to be under the "unhealthy" category on Saturday as the Bangladeshi capital, one of the most polluted cities in the world, registered an air quality index (AQI) score of 160.
With this AQI score, Dhaka is currently the fourth most polluted cities in the world after Lahore, Karachi and Wuhan (China) occupied the top three spots with scores of 180, 169 and 161, respectively.
An AQI between 101 and 200 is considered 'unhealthy', particularly for sensitive groups.
Similarly, an AQI between 201 and 300 is said to be 'poor', while a reading of 301 to 400 is considered 'hazardous'.
Dhaka has long been grappling with air pollution issues. Its air quality usually turns unhealthy during winter and improves during monsoon.
In Bangladesh, the AQI is based on five criteria pollutants -- Particulate Matter (PM10 and PM2.5), NO2, CO, SO2 and Ozone.
With the advent of winter, the city's air quality starts deteriorating sharply due to the massive discharge of pollutant particles from construction works, rundown roads, brick kilns and other sources.