Dhaka has again topped the list of cities around the world with the worst air quality this morning (March 3, 2023).

With an air quality index (AQI) score of 221 at 8:40am, the capital ranked first in the list of world cities with the worst air quality.

An AQI between 151 and 200 is considered "unhealthy," 201 and 300 "very unhealthy," and 301 to 400 is considered "hazardous," posing serious health risks to residents.

Vietnam's Hanoi, Thailand's Chiang Mai and Myanmar's Yangon occupied the second, third and fourth spots in the list, with AQI scores of 207, 198 and 196, respectively.

In Bangladesh, the AQI is based on five criteria pollutants - particulate matter (PM10 and PM2.5), NO2, CO, SO2 and ozone.

Dhaka air was also the most polluted in the world yesterday morning with an AQI of 297.

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 heart disease, chronic respiratory diseases, lung infections and cancer, according to several studies.