Dhaka's air quality continued to be in the ‘moderate’ zone on Friday.

With an air quality index (AQI) score of 66 at 9:06 am, Dhaka today ranked 25th on the list of cities worldwide with the worst air quality.

An AQI between 50 and 100 is considered ‘moderate’ with an acceptable air quality. However, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Also read: Thanks to monsoon, Dhaka's air quality 'moderate' this morning

Indonesia’s Jakarta, Pakistan’s Lahore and Chile’s Santiago occupied the first three spots on the list, with AQI scores of 158, 156 and 153, respectively.

An AQI between 101 and 200 is considered ‘unhealthy’, particularly for sensitive groups.

Similarly, an AQI between 201 and 300 is said to be ‘poor’, while a reading of 301 to 400 is considered ‘hazardous’, posing serious health risks to residents.

Also read: Dhaka's air quality remains in 'moderate' zone

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

As per the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year.

Also read: Dhaka's air 3rd most polluted in the world this morning