As pollution levels soar in Delhi, questions over missing data and transparency raise concerns about the government’s handling of the crisis. 

NEW DELHI – Farmers burning their fields near India’s capital city have caused air pollution in New Delhi to become even worse than it was on Diwali night, 20 October, when the extremely hazardous levels made headlines globally. 

In the past week, the share of stubble burning contributing to Delhi’s pollution had been around 2-3%, but this shot up to 22% on 6 November as farmers raced to clear their paddy fields to sow the next harvest by mid-November. 

Meanwhile, trust in air pollution data has been shaken over the past fortnight, with questions about the Delhi state government’s data collection now the subject of a case in the Supreme Court. 

Since 19 October, the PM2.5 pollution level – the key pollutant usually tracked by experts globally – in Delhi has hovered well above 120 micrograms, falling below 100 only once, while crossing 200 a couple of times. The World Health Organization (WHO) guideline is a PM2.5 average of 15 micrograms per day.  

When New York hit a record PM2.5 level of 117 micrograms on 7 June 2023, officials issued advisories to shut schools, remain indoors and wear masks, but there has been no such advisory in Delhi so far. 

Tampering with air pollution monitors?

But on Diwali night, several air monitors went blank just as pollution from firecrackers started to spike. 

A few days later, on 25 October, opposition legislator Saurabh Bharadwaj released a video showing water being sprinkled around a government-run air monitoring station in the city on Diwali night. 

Bharadwaj’s video showed trucks circling next to a top-grade air quality monitor and spraying it with water. This, he alleged, was to tamper with the data to show lower air pollution numbers.

However, the Commission for Air Quality Management (CAQM) called the allegations “factually incorrect” and “politically motivated” in a 900-word statement sent to Health Policy Watch.

CAQM says the practice is scientific and only for this particular station, Anand Vihar, where pollution is much worse than in other parts of the city.

However, another case was exposed by PeekTV reporters, who also reported that this practice started during the tenure of the earlier government led by Bharadwaj’s party, Aam Admi Party (AAP), but did not specify when or where. 

Last week, Delhi Chief Minister Rekha Gupta also attacked AAP and said air pollution data cannot be manipulated. 

However, there are now suspicions that government data may also under-report the impact of stubble farm fires in states north of Delhi. 

AQ monitors on the blink

Significant data gaps were established on the night of Diwali when Delhi typically sees spikes in PM2.5 levels because of firecrackers. Late that night, around 30 of the 39 monitors stopped reporting continuous data. Only nine worked continuously, the Supreme Court was informed. 

Many air quality monitors didn’t work when most needed: 

At least one monitor recorded PM2.5 levels as high as 1,763 micrograms, before they stopped reporting data altogether. Altogether 163 hours of Diwali AQI data from the peak pollution hours are missing this year, in comparison to only 34 hours last year, a Times of India editorial noted. 

Another data gap: Stubble burning

A much larger data gap has emerged over the farm fires in three states near Delhi. Farmers usually set fire to the residual stubble of their paddy harvest. The practice continues despite being banned by the Supreme Court. Neither the central nor the state governments of Punjab, Haryana and Uttar Pradesh have been able to stop it. 

The contentious part is that data from the Indian Institute of Tropical Meteorology (IITM), a government agency, shows the contribution to Delhi’s pollution of these stubble fires to be far lower than 10% until 5 November, just before the spike. 

The number of fires is declining, the CAQM says. It states that Punjab recorded 2,518 fire counts this year as compared to 4,132 fire counts in 2024. Similarly, in Haryana 145 fire counts were recorded this year as compared to 857 in 2024. 

But other data seems to contradict this, suggesting that the stubble fires are indeed polluting Delhi and the rest of north India. 

In fact, there are 25% and 33% more fires this year than in 2020 and 2024, according to Hiren Jethva, a scientist at NASA. 

Jethva told HPW that IITM model projections are based on NASA/NOAA satellite fire detection, which miss the late afternoon burning. Last year, he showed Health Policy Watch that farmers had worked out how to evade the satellite imagery used by officials by starting the fires after the satellite completes its pass. 

A massive sea of smoke now blankets the Indus Valley and much of northern India, triggering an air quality emergency across the region. Stubble bunring must be controlled to avoid such #AirQuality disaster. Build up a chorus loud enought to be heard in Parliament and assemblies. pic.twitter.com/PA97ojdjPq

— Hiren Jethva (@hjethva05) November 3, 2025

The other contradiction, according to a Delhi-based senior air quality researcher who spoke with HPW, is the amount of carbon monoxide (CO) in Delhi’s air.

The chart below, shared by the researcher, shows spikes in CO levels in April-May and October-November, when crop residue is burnt in the northern states. The latest data show a spike this time of year as well. 

Adding to the controversy, the Delhi government went ahead with cloud seeding flights to try to start rain on 28 October despite warnings from the Indian Meteorological Department that there was insufficient cloud or moisture in the atmosphere to result in rain, according to The Hindu.

What the government has not tried yet is curbs on vehicle emissions, except on some types of trucks and vans from outside Delhi. Vehicular pollution in Delhi has been around 15-20% in the last few days, according to IITM. 

Lack of trust

As many as 87% of Delhi residents reportedly do not trust air quality data from the government’s monitors, a post-Diwali survey found. Governments have invested in monitors, systems, scientists, and research but data transparency and communication remain poor given the magnitude of the crisis – and the outrage. 

Restoring trust will require more than just PR and top-down statements.

Meanwhile, local doctors point out the damage they see in patients as a result of air pollution, and at least one has advised residents to leave the national capital for six to eight weeks if they can afford it. 

Dr Naresh Trehan, a renowned cardiologist at Medanta Hospital, says they see blackened lungs every day in heart operations. 

“Exposure to high particulate matter in the air… creates black marks around the lungs,” Trehan explained to the news agency, PTI. “Oxygen transmission across the membrane of the lung becomes obstructed. So the lack of oxygen in the blood causes damage to every organ, including the heart.” 

Image Credits: The Week, Delhi Pollution Control Board, Vidyut Mohan.