Bangladesh’s capital Dhaka ranked fourth worst in Air Quality Index (AQI) on Monday morning.

The capital city had an AQI score of 197around 10am as the air was classified as ‘unhealthy’.

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

Pakistan’s Lahore, Afghanistan’s Kabul and India’s Delhi occupied the top three spots with AQI scores of 426, 395 and 224, which is classified as ‘Hazardous’ and ‘very unhealthy’ respectively.

Air quality in this ‘hazardous’ range triggers health warnings of emergency conditions by media outlets. Besides, when air quality is in this 'very unhealthy' range, it is expected that there will be widespread effects among the general population and more serious effects in members of sensitive groups.

AQI, an index for reporting daily air quality, is used by government agencies to inform people how clean or polluted the air of a certain city is, and what associated health effects might be a concern for them.

Read: Dhaka breathes ‘unhealthy’ air as AQI dips

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 during winter and improves during monsoon.

Environmental experts have stressed the need for effective measures to protect Dhaka city dwellers from air pollution during the winter when it usually turns unhealthy and hazardous.

They suggest sweeping the city’s roads with water regularly, covering construction sites and materials, and stopping the movement of overloaded and unfit motor vehicles in the city.

The experts blame the authorities concerned for their lack of seriousness as no visible steps are seen yet to improve the air quality, which worsens terribly from November to February.

From January to March in 2021, the air quality was hazardous for 12 days, very unhealthy for 58 days, unhealthy for 19 days and unhealthy for sensitive groups in one day in Dhaka, one of the most polluted cities in the world.

Read: Experts lament lack of steps to check air pollution in Dhaka city

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, as per the World Health Organization (WHO).