The air quality in Dhaka has been in the "hazardous" zone for the second consecutive day, on Saturday.

With an air quality index (AQI) score of 329 at 9:07 am, the capital of Bangladesh ranked first in the list of cities worldwide with the worst air quality, reports UNB.

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.

Ghana’s Accra, China’s Beijing and Pakistan’s Lahore occupied the second, third and fourth spots in the list, with AQI scores of 266, 223 and 200, respectively.

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.