Lahore, Karachi remain among top four polluted cities on AQI

LAHORE: Lahore ranked third and Karachi fourth most polluted city on the index pointing out unhygienic air quality, ARY News reported on Thursday.

Pakistan’s two largest cities have got the dubious distinction of soaring to third and 4th from the top in the most polluted cities of the world on the air pollution measurement scale.

Lahore has been measured to have 204 reading on the Air Quality Index (AQI), while Karachi have an AQI reading of 191 with regard to hazardous particles in the air.

The Environment Protection Department in its air quality update today reported 115 reading at Town Hall, Mall Road in Lahore. AQI reading remained 96 at Township and 249 at Karol Ghati, according to a spokesperson of the environment department.

It is to be mentioned here that AQI as high as 151-200 is considered unhealthy, while an AQI reading between 201 to 300 is more harmful and AQI rate over 300 mark is extremely hazardous.

According to experts, the air becomes heavier in the winter as compared to summer, causing poisonous particles in the atmosphere to move downwards and making the atmosphere polluted. As a result, a layer of polluted particles, including large amounts of carbon and smoke, covers an area.

The smoke produced by factories or by burning coal, garbage, oil or tyres, enters the atmosphere and its impact appears at the onset of the winter and remains till the end of the season, experts said.

The AQI calculation is based on five categories of pollution: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.

Although southwestern winds blowing from the sea in Karachi may work as a filter for the air, however these winds remain mostly suspended during the winter, according to experts.

The winds blowing from the northeast increase concentration of polluted particles, and a healthy atmosphere in such a situation is subject to the rainfall, which washes off polluted particles.