Lahore and Karachi have been featured on the list of the worlds top five most polluted cities bagging second and the third rank respectively, media reported on Friday.
As per the recent air pollution data released by the US Air Quality Index, Lahore showed a particulate matter (PM) rating of 181, placing it in the second position on the global index of most polluted cities.
On the other hand, with a particulate matter (PM) rating of 172, Karachi was ranked the third most polluted city in the world.
According to the standards set by the Air Quality Index, a city is categorized as unhealthy if the particulate matter rating lies between 151 and 200. A rating between 201 and 300 is categorized as highly unhealthy and anything above 301 falls under the hazardous category.
Meanwhile, experts stated that the air becomes heavier in the winter as compared to summer, producing poisonous particles in the atmosphere to move downwards and making the atmosphere polluted. Consequently, a layer of polluted particles, including large amounts of carbon and smoke, covers a city.
The smoke produced by factories and burning garbage, oil or tyres enters the atmosphere and the effects of this appear at the start of winter and remain till the seasons end, experts said.
It is to be mentioned that the Lahore High Court (LHC) last week ordered the concerned authorities to impose a?smog emergency in Punjab?ahead of the winter season.
Media reported that Justice Shahid Jamil heard a petition, asking the government to take measures to control the smog in the province.
In addition, the LHC also directed Chief Secretary Punjab to call upon a meeting to take precautionary actions ahead of the winter season.
The court also directed to close down the smoke-emitting factories immediately. Immediate action should be taken against people involved in burning the crop, the court concluded.