Dhaka's air quality continued to be in the 'unhealthy' zone on Friday morning.
With an air quality index (AQI) score of 161 at 8:45am, the metropolis ranked eighth in the list of world cities with the worst air quality.
Russia’s Krasnoyarsk, Pakistan’s Lahore and India’s Mumbai occupied the first, second and third spots in the list, with AQI scores of 271, 191 and 175, respectively.
An AQI between 201 and 300 is said to be 'poor', while a reading of 301 to 400 is considered 'hazardous', posing serious health risks to residents.
In Bangladesh, the AQI is based on five criteria pollutants -- Particulate Matter (PM10 and PM2.5), NO2, CO, SO2 and Ozone.
Dhaka has long been grappling with air pollution issues. Its air quality usually turns unhealthy in winter and improves during the monsoon.
Air pollution consistently ranks among the top risk factors for death and disability worldwide. Breathing polluted air has long been recognised as increasing a person’s chances of developing a heart disease, chronic respiratory diseases, lung infections and cancer, according to several studies.