Dhaka’s air quality continued to be in the ‘unhealthy’ zone on Thursday morning, reports news agency UNB.

With an air quality index (AQI) score of 175 at 8:49 am, the capital of Bangladesh ranked third in the list of cities worldwide with the worst air quality.

India’s Delhi and Mumbai occupied the first and second spots, with AQI scores of 214 and 188 respectively.

An AQI between 151 and 200 is considered ‘unhealthy’ while between 201 and 300 is ‘‘very unhealthy’, and 301–400 is ‘hazardous’, posing severe 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.

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.