New Delhi– The Air Quality Index (AQI) in Delhi plunged to its worst levels in five years on Tuesday morning, according to a report analysing Central Pollution Control Board (CPCB) data. The study, conducted by Climate Trends, found that post-Diwali PM2.5 concentrations averaged 488 µg/m³, marking a 212% increase from pre-Diwali levels.

Pollution spikes despite decline in stubble burning

The findings come as a surprise, given that stubble burning incidents fell 77% this October due to widespread floods in Punjab and Haryana, which delayed paddy harvesting. The report highlights that while curbing farm fires plays an important role in air quality improvement, firecracker emissions remain the dominant cause of Delhi’s short-term pollution surge during Diwali.

“Firecrackers continue to drive Delhi’s toxic air levels during the festival, causing an immediate collapse in AQI readings,” the Climate Trends analysis noted.

Political blame game over Delhi’s air crisis

The worsening air quality has reignited a political blame game between the Aam Aadmi Party (AAP) and the Bharatiya Janata Party (BJP).

Delhi Environment Minister Manjinder Singh Sirsa accused AAP of “forcing Punjabi farmers to burn stubble” ahead of Diwali. At a press conference on Tuesday, Sirsa showed videos purportedly from Tarn Taran and Bathinda, claiming farmers were being coerced to ignite crop residue while hiding their identities.

“The Aam Aadmi Party, which has run an incompetent government in Delhi for the last ten years, has been involved in questionable activities. These visuals prove farmers are being forced to burn stubble,” Sirsa alleged.

Responding sharply, AAP Delhi president Saurabh Bharadwaj criticised the government’s handling of post-Diwali pollution and questioned the failure to implement the promised ‘artificial rain’ to improve air quality.

Report shows consistent Diwali-related pollution spike

An analysis of CPCB data from 2021 to 2025 shows a consistent rise in PM2.5 levels during Diwali each year. The 2025 festival, however, stands out as the most polluted in recent history.

According to Palak Balyan, Research Lead at Climate Trends, “This year’s Diwali has proven to be worse than before. The data shows a sharp rise in PM2.5 readings from 156.6 µg/m³ pre-Diwali to 488 µg/m³ post-Diwali — more than a threefold jump.”

The analysis also recorded peak concentrations of 675 µg/m³ on the night of October 20, directly corresponding to the widespread bursting of firecrackers across Delhi-NCR.

Are green crackers truly sustainable?

The pollution spike followed the Supreme Court’s decision to allow the sale and use of ‘green crackers’ for a two-hour window during Diwali celebrations. Despite the restrictions, residents were seen flouting the order and bursting crackers well beyond the permitted hours.

Chief Justice of India BR Gavai had directed the CPCB and State PCBs to monitor the AQI between October 18 and 21, but early data suggests that green crackers provided no measurable improvement over conventional ones.

“Visuals and ground data confirm that the so-called green crackers made no difference. Allowing them during this season is simply unsustainable,” Balyan added.

Experts link pollution surge to local emissions

Experts studying the Climate Trends report emphasised that the severe spike in PM2.5 levels was local in nature, not caused by transported pollutants.

Dr S.K. Dhaka, Professor at Rajdhani College, University of Delhi, explained, “Wind speeds were below 1 m/s, preventing pollutant dispersion. Relative humidity ranged between 60–90%, with higher moisture trapping pollutants closer to the ground.”

He added that temperature inversion — a drop from around 27°C to 19°C post-Diwali — worsened the situation by creating conditions that trapped particulate matter.

“We conclude that even green firecrackers raised particulate matter rapidly, and the pollution is primarily of local origin. This raises questions about the true effectiveness of green crackers,” Dhaka said.

Key findings of the Climate Trends report

  • Post-Diwali PM2.5 average: 488 µg/m³ – a 212% rise from pre-Diwali levels.
  • Peak PM2.5 concentration: 675 µg/m³ late night on 20 October 2025.
  • Wind speeds: Below 1 m/s, limiting dispersion.
  • Temperature drop: From ~27°C to ~19°C, creating inversion conditions.
  • Pattern: PM2.5 values typically double or triple during Diwali night and persist through the next day.
  • Trend: 2025 recorded the highest mean and maximum post-Diwali concentrations across five years.

Experts call for stronger enforcement and innovation

Environmentalists are urging the Delhi government to enforce stricter firecracker bans and invest in sustainable air quality solutions, including artificial rain and industrial emission controls.

“Until there’s political will and public cooperation, Delhi will continue to experience these toxic post-Diwali spikes,” said Balyan.

With winter approaching, stagnant wind conditions and lower temperatures are expected to further worsen Delhi’s AQI levels in the coming weeks.