Dhaka's air quality was categorised as “unhealthy for sensitive groups” Saturday morning.

With an Air Quality Index (AQI) score of 121 at 8:53am, Dhaka ranked 10th on the list of cities worldwide with the worst air quality.

Thailand’s Chiang Mai, India's Delhi, Nepal’s Kathmandu and Indonesia’s Jakarta occupied the first four spots on the list, with AQI scores of 173, 167, 164 and 162, respectively.

When the AQI value for particle pollution is between 101 and 150, air quality is considered “unhealthy for sensitive groups”, between 150 and 200 is “unhealthy”, between 201 and 300 is said to be “very unhealthy”, while a reading of 301+ 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.

As per the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year, largely as a result of increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.