Dhaka has ranked sixth on the list of cities with the worst Air Quality Index (AQI) score of 141 at 9:50am on Wednesday morning.

Wednesday’s air was classified as "unhealthy for sensitive groups," referring to a health threat, according to the AQI index.

Pakistan’s Lahore, India’s Delhi and United Arab Emirates’ Dubai cities respectively occupied the first, second and third spots on the list, with AQI scores of 172, 163 and 160 respectively.

The AQI, an index for reporting daily air quality, informs people how clean or polluted the air of a certain city is and what associated health effects might be a concern for them.

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.