This is because the densely populated capital is no longer the world’s worst most polluted city -- it has slipped to the sixth position in the list of cities with the worst air quality.

Also read: Dhaka’s air quality remains 'unhealthy'

On Saturday, the capital's air quality index (AQI) was recorded at 190 around 10.40 am.

China’s Shenyang, Saudi Arabia’s Riyadh and Thailand’s Chiang Mai occupied the first three spots with AQI scores of 280, 261 and 229, 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.

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.

In Bangladesh, the AQI is based on five criteria pollutants - Particulate Matter (PM10 and PM2.5), NO2, CO, SO2 and Ozone.

Also read: Air quality: Dhaka world's second-most polluted city

Dhaka has long been grappling with air pollution. Its air quality usually improves during monsoon.

In recent months, the air quality has degraded to such a degree that the High Court had to issue a nine-point directive for taking steps to improve the quality.

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.

Also read:  Dhaka no longer world's most polluted city, but air quality still 'poor'

Over 80 percent living in urban areas, which monitor air pollution, are exposed to air quality levels that exceed WHO guideline limits, with low- and middle-income countries most at risk.