Smog is once again threatening to choke Lahore and other cities across Punjab, as Pakistan sees a steady rise in carbon emissions and braces for toxic air pollution blowing from northern India, including New Delhi.

The layer of smog, enveloping the provincial metropolis for the past two days, has been thickening, reducing visibility and making breathing difficult for the residents.

Air pollution caused by traffic, industries, crop burning and disposal of solid waste are major contributors to smog.

With Pakistan witnessing a steady rise in carbon emissions, the smog is only expected to worsen in the forthcoming winters unless urgent action is taken, World Wildlife Fund (WWF) Pakistan has warned.

Lahore and Karachi are among 10 most polluted cities of the world in terms of air quality, according to air quality monitor Air Visual, CEO WWF Pakistan, Hammad Naqi Khan, said while speaking at the launching ceremony of WWF's Living Planet Report 2018 on Tuesday.

"The ranking today puts Lahore at the top of the list, and urgent action needs to be taken to tackle this issue," he said.

He informed that the urban air pollution in Pakistan is among the world's most severe, significantly damaging human health, quality of life, economy and the environment.

Khan urged people to move around with face masks to protect themselves against breathing problems, eye, nose, and throat infections.

Furthermore, Adviser to the Prime Minister on Climate Change, Malik Amin Aslam has assured that the government is taking all possible steps to control smog in the country.

The minister said in a statement that cross-border crop burning has increased and continues unabated even though Pakistani Punjab has controlled the issue from its side.

Aslam said the government has taken up the issue of trans-boundary pollution due to burning of crop leftovers with India.

He said there are four major sources of smog: smoke-emitting vehicles, brick kiln, industry and crop burning.

The minister informed that brick-kiln owners had voluntarily agreed to shut down their kilns from October to December and that they would shift their kilns on modern zigzag technology which reduces smoke.

He said that the government would establish 11 air monitoring stations in and around Lahore.

“Of these, three stations have been activated in Gujranwala, Faisalabad and Multan, whereas eight stations would be established in the city area,” he shared, adding that a special smog desk would be established in hospitals from where citizens can get help regarding smog-related issues, like asthma.

Crop stubble burning, a major source of pollution, vehicular exhaust and a drop-off in wind speeds have aggravated the smog in and around New Delhi, which is likely to worsen around November 7, when fireworks will set off to celebrate the major Hindu festival of Diwali.