Karachi ranked third in world's most polluted cities' list

KARACHI: Karachi has soared among top three most polluted cities of the world on Thursday, ARY News reported.

Kazakhstan’s capital city Nur-Sultan (Astana) reached to top of the Air Quality Index and Bangladesh’s capital Dhaka remained second in the AQI list of most polluted cities with poor air quality.

Pakistan’s largest city Karachi, ranked third from the top in the AQI list with 189 points.

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 termed extremely toxic.

According to experts, an increase in air pollution used to be recorded in the winter. 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 a city.

The smoke produced by burning crop remnants, 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 said.

Thus air pollution reaches to extremely dangerous levels, severely compromising the air quality.