Punjab Chief Minister Shahbaz Sharif on Sunday wrote to his Indian counterpart regarding the "aggravated and widespread" problem of smog that the people of Punjab ─ the province in Pakistan and the bordering state in India ─ have had to face over the past weeks.

In a letter dated Nov 19, Shahbaz invited Chief Minister of Indian Punjab Captain Amarinder Singh to enter into "a regional cooperation arrangement to tackle the issue of smog and environmental pollution."

"The people of Pakistani and Indian Punjabs have been facing the problem of smog during the months of October and November," the chief minister wrote, adding that the problem had worsened in the current year.

Shahbaz went on to detail to the causes of smog: vehicular and industrial emissions and rice stubble-burning. He further identified the adverse impact of smog in terms of public health, agricultural production and road safety.

"The phenomenon has now assumed regional proportions and it engulfs areas from New Delhi to Lahore and beyond. You will agree with me that the problem is mainly scientific and economic and cannot be tackled through any other means," Shahbaz wrote, adding that through the identification of technologies and business methods the problem can be controlled.

"Let us join hands for securing a prosperous future," he concluded.

World's most polluted capital

Delhi's air quality typically worsens ahead of the onset of winter as cooler air traps pollutants near the ground, preventing them from dispersing into the atmosphere, a phenomenon known as inversion.

The World Health Organisation in 2014 classed New Delhi as the world's most polluted capital, with air quality levels worse than Beijing. Since authorities have taken measures to address the problem, such as the temporary closure of power plants. This year India's top court also ordered a temporary ban on the sale of firecrackers in New Delhi.

However, many have criticised the measures as insufficient in tackling the issue. On Nov 7, a public emergency was declared in New Delhi when a choking blanket of smog descended on the Indian capital. Low visibility caused by the smog had forced the closure of one of the runways at Delhi airport, delaying some flights.

A recurring pre-winter feature

Similarly, in Pakistan this year the Punjab's Environment Protection Department (EPD) sprung into action to tackle what has been identified as a recurring pre-winter feature.

One hundred and thirteen factories were sealed and 250 vehicles were fined after Lahore was engulfed by hazardous smog ahead of the winter season for the second year in a row.

Officials at the EPD have admitted lack of capacity and resources to deal with the smog. The department, however, has been blamed for wasting the equipment it has. Ten years ago, three air quality monitoring machines were acquired from a Japanese firm. A decade later, these instruments have rusted, as the EPD admits itself. If they were used, as officials claim they were, no one knows the air quality readings received as they were never made public.