After a brief improvement in rankings, South Asian cities including India’s Delhi and Pakistan’s Lahore have once again reappeared on the list of the world’s most polluted cities and Bangladesh’s Dhaka maintained a comparatively satisfactory position on Monday morning.

According to the latest Air Quality Index (AQI) report, Dhaka’s air quality showed signs of improvement with an AQI score of 77 at 9am and it ranked 21st on the list of polluted cities.

Dhaka’s air was classified as ‘moderate,’ referring to a light health threat, according to the AQI index.

Lahore ranked second with an AQI score of 162, while Delhi followed in third place with a score of 156.

The Congolese capital, Kinshasa, topped the list as the world’s most polluted city with an AQI reading of 165.

Indonesia’s Jakarta and Uganda’s Kampala occupied the fourth and fifth positions respectively, with AQI scores of 155 and 153.

All top five cities on the list recorded air quality levels classified as ‘unhealthy.’

Dhaka’s air ‘moderate’ this morning

 According to the AQI scale, when the AQI value for particle pollution is between 50 and 100, air quality is considered ‘moderate’, usually sensitive individuals should consider limiting prolonged outdoor exertion, 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.

The AQI in Bangladesh is based on five 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.

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