Karachi [Pakistan], January 17 (ANI): Karachi found a place among the world's most polluted cities when the level of hazardous particles in the air touched 324 on Sunday, according to ARY News.
Citing the reading of the Air Quality Index (AQI), ARY News reported that air pollution of particulate matter in Lahore was recorded 171, Peshawar 414, and Islamabad 171.
The air pollution in Karachi has reached dangerous levels, an expert said adding that in winter an increase in air pollution is witnessed. Smoke from factories and vehicular traffic in cities are some of the factors causing air pollution.
The smoke produced by factories and burning coal, garbage, oil or tyres enters the atmosphere and the effects of this appear at the onset of winter and remain till the season's end, experts added.
AQI as high as 151-200 is considered unhealthy, while an AQI between 201 to 300 is more harmful and an AQI over 300 is dubbed extremely hazardous, ARY News reported.
The AQI is calculated on the basis of five categories of pollution, including ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. (ANI)