The Commission for Air Quality Management in National Capital Region on Thursday banned the plying of diesel-run four-wheelers in Delhi and adjoining in view of the deteriorating air quality, PTI reported.

The panel also ordered to stop the entry of trucks, other than those used for carrying essential goods or emergency services, into Delhi.

A thick layer of smog engulfed Delhi on Thursday as the air quality deteriorated to the “severe” category.

The city’s 24-hour average Air Quality Index stood at 450 at 4 pm, up from 439 at 1 pm, according to Central Pollution Control Board data.

An air quality index ranging between 401 and 500 falls under the “severe” category. A reading of above 400 can affect healthy persons and seriously impact those with existing illnesses.

The levels of the PM2.5 fine particles in the air was 308 micrograms per cubic meter, falling under the “severe” category, according to SAFAR.

Particulate matters smaller than 2.5 microns (or about ten-thousandth of an inch) are particularly dangerous to human health. Such particles are small enough to travel deep into the respiratory system, potentially impairing lung function.

To be considered safe, the National Ambient Air Quality Standards require PM2.5 concentration in air to be less than 60 micrograms per cubic metre in any given 24-hour period.

Air quality deteriorates sharply in the winter months in Delhi, which is often ranked the world’s most polluted capital. Stubble burning in Punjab and Haryana, along with falling temperatures, decreased wind speed and emissions from industries and coal-fired plants contribute to air pollution.

On Thursday, the Commission for Air Quality Management also said that the Delhi government may take a call on closing educational institutes, non-emergency commercial activities and plying of vehicles on an odd-even basis.

It also asked the Centre to decide whether work from home can be permitted for government employees and directed to close industries running on non-clean fuels.

“Children, elderly and those with respiratory, cardiovascular, cerebrovascular or other chronic diseases to avoid outdoor activities and stay indoors, as much as possible,” the panel said, according to ANI.

Political leaders trade barbs

Meanwhile, political leaders criticised each other for the situation in the national capital.

On Wednesday, Union Environment Minister Bhupender Yadav blamed the Aam Aadmi Party government for turning Delhi into a gas chamber, saying that there has been a 19% rise in stubble burning in Punjab as compared to last year.

“Just today [Wednesday], Punjab saw 3,634 [farm] fires,” Yadav said in a series of tweets. “There is no doubt over who has turned Delhi into a gas chamber.”

Yadav accused the Aam Aadmi Party that rules Delhi and Punjab of carrying out a scam.

He alleged that the Punjab government bought 1.2 lakh crop residue management machines from Rs 1,347 crore given by the Centre in five years. The minister alleged that 11,275 of these machines have gone missing. “Money utilisation shows clear incompetence,” he wrote.

He also alleged that the Punjab government “chose to sit with” about Rs 492 crore of funds given by the Centre for crop residue management machines, forcing farmers to resort to stubble burning.

“The chief minister of Punjab [Bhagwant Mann] has failed to even provide relief to farmers in his own turf of Sangrur,” he added. “Last year [September 15-November 2] farm fires in Sangrur stood at 1,266. This year they have shot up by 139% rising to 3,025.”

Responding to the criticism, mainly levelled by BJP leaders, Delhi Chief Minister Arvind Kejriwal said that the high pollution level was a problem for all northern states.

“So, has the Aam Aadmi Party caused pollution everywhere?” he asked, adding that the issue has been politicised and no one is looking for a solution.

Kejriwal said that since air quality problem affects all northern cities, the onus is on Prime Minister Narendra Modi to do something about it.

The chief minister also claimed that the Centre had rejected his government’s proposal to tackle the farm fires.

Amid the deteriorating situation, the Commission for Air Quality Management on October 29 had directed authorities in the National Capital Region to immediately implement restrictions under stage III of the Graded Response Action Plan – a step-by-step emergency measures to fight the pollution.

Under stage III, restrictions include a ban on construction and demolition activities, except for essential projects concerning national security, defence, railways and metro rail, among others.

On Wednesday, the National Commission for Protection of Child Rights had urged the Delhi government to close schools till air quality improves.

Farm fires account for 38% of Delhi pollution

The share of stubble burning in Delhi’s pollution increased to 38% on Thursday, according to SAFAR, PTI reported.

Gufran Beig, the project director of the agency, said that share of crop burning in air pollution was “quite significant”. He said that Noida currently has the worst air pollution as it falls in the path of emissions from stubble burning, while Gurugram and the Lodhi Road area in Delhi are the least affected.

“The overall air quality in Delhi will continue to remain in the severe category till Friday morning,” Beig said. “There will be slight improvement afterwards. A major relief is likely on Saturday due to predicted improvement in meteorological conditions – wind speed and direction.”

Meanwhile, an analysis by the Centre for Science and Environment said that from October 21 to October 26, emissions from vehicles contributed about 51% to PM2.5 levels out of the local sources of pollution in Delhi, according to The Indian Express.

Thirteen percent of the pollution was from residential sources, while 11% from industries, as per the analysis.