“We are concerned with the level of smog in the city of Delhi. With each passing day, the smog level is rising. Everyday we are also hearing about the rising level of pollution in the city. We will deal with the matter,” said a bench led by Chief Justice Altamas Kabir.

The bench made this observation while hearing a PIL relating to contamination of ground water after the Bhopal gas leak and disposal of waste at the site. The court remarked that it might take up the issue pertaining to the smog cover over Delhi since there were reports that increase in pollution could have caused it.

Advocate Vijay Panjwani, who appeared for the Central Pollution Control Board in the matter, linked the problem to increase in the number of vehicles in the city. “The smog is likely due to a massive increase in the number of diesel vehicles in the city,” he said.

Meanwhile, the smog that has enveloped the city for over a week now is likely to stay at least until Thursday afternoon. Officials of the meteorological department said continued effects of external factors like Cyclone Nilam were delaying westerly winds, thereby continuing the smog presence.

Dr R K Jenamani, Director-in-charge of the IGI meteorological department, said: “External factors are responsible for almost 30 per cent of the existing smog. There is a continued vertical effect of Cyclone Nilam. It is still causing heavy rain in Andhra Pradesh and Karnataka, and generating moisture in the north. This is also delaying westerly winds in Delhi, so the smog will persist at least until Thursday afternoon.”

Experts say local factors like lack of lateral winds and high pollution levels — nearly 8-10 times the prescribed national standard — have also aggravated the smog since suspended particles in the atmosphere were not diffusing.

“The relative humidity levels have been nearly 70-75 per cent, and hardly any wind. Visibility has hovered between 800-1000 metres,” a scientist said. On Wednesday, shallow fog is expected to persist at least in the forenoon.

Delhi has been under smog cover since October 28 though conditions improved somewhat on November 3. But the vertical effects of the cyclone in the south and high pollution levels intensified the smog again on November 4. Met department officials said November 4 saw the thickest smog cover, mainly due to stagnation of dust and pollution due to low wind speed. Visibility at the airport was the poorest on November 4.

What led to the smog?

Smog cover over Delhi on October 28

Intensifies as Cyclone Nilam strikes Tamil Nadu coast on November 1

Rainfall in South and Central India pushes up humidity level in Delhi