Dhaka’s air worst in the world this Friday

On Friday morning, Dhaka once again topped the list of global cities with the poorest air quality.

The capital Dhaka was at the top of the list of cities with the worst air at 8 am today, with an air quality index (AQI) score of 317.

An AQI of 151 to 200 is considered "unhealthy," 201 to 300 is "very unhealthy," and 301 to 400 is "hazardous," offering major health concerns to locals.

Kolkata and Mumbai, both in India, came in second and third on the list, respectively, with AQI scores of 196 and 189.

The AQI is based on five criteria pollutants -- Particulate Matter (PM10 and PM2.5), NO2, CO, SO2 and Ozone in Bangladesh.

Dhaka has long been grappling with air pollution issues. Its air quality usually turns unhealthy in winter and improves during the monsoon.

According to the World Health Organization (WHO), air pollution kills an estimated seven million people every year throughout the world.