LAHORE: Punjab’s capital city Lahore remains second from the top of the world’s most polluted cities list on Tuesday, ARY News reported.
Average reading of Lahore on the Air Quality Index measured 191 today.
Karachi, the largest city of Pakistan, placed 5th among the world cities with regard to worst air quality.
The AQI is calculated on the basis of five categories of pollution: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.
AQI as high as 151-200 is considered unhealthy, while an AQI rating between 201 to 300 is more harmful and AQI over 300 is extremely hazardous.
According to experts, an increase in air pollution used to be recorded in the winter. A change in the wind speed, wind direction and sliding minimum temperature increases air pollution.
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 burning crop remnants, factories and burning coal, garbage, oil or tyres enters the atmosphere and the impact of this appear at the onset of winter and remains till the season’s end, experts said.
