Air pollution in the national capital region (NCR) worsened on Wednesday, repeating a trend that exposes how efforts put in place in recent years — Supreme Court orders, new laws, penalties, and even cleaner fuel — have failed to stop the recurrence of an annual crisis that plunges the region into a public health emergency.

In conditions similar to last year, Wednesday’s was the second consecutive “severe” air quality day in the three days following Diwali, during which there was rampant use of illegal firecrackers in defiance of Supreme Court orders that only green crackers could be used in the region between 8pm and 10pm.

According to the Central Pollution Control Board’s (CPCB) 4pm bulletin, Delhi’s average air quality index for the 24-hour period since Tuesday stood at 419. The day before, it was 400. Air quality is considered ‘good’ when AQI is lower than 50.

Delhi’s air quality takes a hit post Diwali, plunges to ‘very poor’ category
Air quality in Delhi took a hit after the Diwali night due to firecracker emissions and stubble burning. Pollution levels have been oscillating between lower end and higher end of ‘very poor’ category.

Ghaziabad, at 478, recorded the worst AQI of the 102 cities mapped by CPCB. The AQI in Noida was 450, Greater Noida 438, Faridabad 404, and Gurugram 365.

On Wednesday, as calls grew for authorities to take more measures, the Delhi and Noida administrations issued advisories asking schools to suspend all outdoor activities till the air clears up and CPCB recommended that curbs announced earlier this month – such as banning overnight construction work – will be extended till Saturday.

The curbs are part of the Graded Response Action Plan (Grap) that lays down sets of restrictions when AQI crosses certain thresholds – the most serious of these include a ban on trucks, odd-even road restrictions, an embargo on construction work, and an advisory to governments to shut schools.

But these don’t come into force unless the threshold has been breached for 48 consecutive hours – a rule that is now under scrutiny. “A proposal has already been submitted to Epca to re-evaluate Grap. We need to have a re-look at what preventive measures should be enforced at what time, and how much Grap measures are helping – a quantitative analysis. The proposal was sent by IIT Madras and NEERI. So far nothing has been done,” said Mukesh Khare, a member of Epca, which enforces Grap, and a professor of civil engineering at IIT Delhi.

Delhi’s chief minister Arvind Kejriwal said he will meet the head of Environment Pollution (Prevention and Control) Authority (Epca) to discuss what additional measures can be taken. “We will implement every measure that is mentioned in the Graded Response Action Plan (Grap). I am going to meet the chairman on Friday and discuss what other measures we can take,” he said on Wednesday.

Top medical experts said steps must be taken to restrict exposure to pollution, particularly of vulnerable people such as the elderly and children.

“Air pollution mainly affects the lungs, but more and more data shows it affects the entire body. For people who are breathing poor quality air for more than 10 years, apart from lung cancer, it causes inflammation in blood vessels running through the lungs and the rest of the body. It leads to atherosclerosis or the hardening of the arteries, which predisposes people to heart attacks and stroke,” said Dr Randeep Guleria, director, AIIMS.

He added that out outdoor physical activity should be restricted for children. “You should wait for the sun to come out and to at least for the pollutants to rise up,” he said.

For the entirety of Wednesday and most of Tuesday, the sun was hardly visible.

Sunlight helps break a crucial meteorological phenomenon that exacerbates pollution. Typically, as the weather changes from monsoon to winter, winds start blowing in from the northwest – the region where farmers are usually setting crop residue spread over acres of acres land on fire during this time of the year.

As the smoke channels in towards NCR and much of the Indo-Gangetic plains, the cooling of the air drags it down – blanketing towns and cities in a choking haze that is also made up of local emissions. It is in such circumstances that strong sunlight, if it can penetrate the haze, helps warms the air and disperse the pollutants.

According to an analysis of data from Nasa’s Visible Infrared Imaging Radiometer Suite (VIIRS), there were 18,162 fires spotted in Punjab and Haryana between October 20 and 30 – significantly higher than the 14,897 seen in the same period last year.

The Punjab Remote Sensing Centre said 3,135 crop burning incidents were recorded on Wednesday – the highest for a single day ever recorded. The previous was 2,975 incidents in 2017.

“The main reason for so many fires this year is because farmers haven’t gotten equipment to manage crop residue. Some farmer societies were formed and they received government funds and bought the equipment, but the number is very small,” said Rattan Mann, president of Bharatiya Kisan Union (BKU). He added that the problem is worse this year because of a delayed harvest – which has forced farmers to prefer burning the residue that takes less time.

A senior environment ministry official too said the effort to wean farmers off the harmful practice had not paid off. “The subsidy scheme seems to have failed. We had transferred the money and the state governments assured that equipment will be distributed,” this official said, asking not to be named.

In one Punjab district, Sangrur, the district magistrate said 144 fines totalling ₹3.6 lakh were collected from farmers caught burning crop residue. The fine of ₹2,500 per is often lower than what a farmer would spend on renting a harvesting machine with the stubble management device on a mid-to-large sized farm.