Online Desk: Dhaka continued to occupy the top spot in the list of cities around the world with the worst air quality for the third consecutive day this morning. With an air quality index (AQI) score of 288 at 9:30am, the capital of Bangladesh ranked first in the list of 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. India’s Mumbai, China’s Beijing and Thailand’s Chiang Mai occupied the second, third and fourth spots in the list, with AQI scores of 203, 198 and 192, respectively.

Dhaka air was also the most polluted in the world yesterday morning with an AQI of 221. 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 heart disease, chronic respiratory diseases, lung infections and cancer, according to several studies.