The air quality of Dhaka showed a sign of improvement on Wednesday morning.

The capital ranked 18th worst in the Air Quality Index (AQI) with a score of 118. The air quality was classified as ‘unhealthy’.

China’s Shenyang, Chengdu, Guangzhou occupied the first three spots in the list of cities with the worst air with scores of 189, 176 and 171 respectively.

When the AQI value is between 101 to 150 it means ‘Unhealthy for Sensitive Groups’.

Although general public is not likely to be affected at this AQI range, people with lung disease, older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air.

Bangladesh has shut down educational institutions, mass transport, and non-essential services and restricted the movement of people and vehicles to tackle the spread of coronavirus. People have been asked to stay indoors.

This has significantly cut down air pollution in Dhaka which regularly ranks among top 10 cities with worst air quality.

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.

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. Its air quality usually improves during monsoon.