On the morning after Diwali in October 2025, New Delhi awoke to a familiar yet deeply troubling sight: a dense, toxic smog blanketing the city skyline, the Yamuna River shrouded in haze, and residents donning masks or cloths over their faces as they braved the outdoors. According to BBC, the air quality in India’s capital had surpassed the United Nations’ daily norms by a staggering 23 times on October 21, 2025, marking one of the worst pollution episodes in at least four years. The city’s air quality index (AQI) fluctuated between ‘poor’ and ‘very poor’, with some monitoring stations reporting ‘severe’ levels, painting a grim picture for the 20 million people who call Delhi home.
As CNN reported, New Delhi’s PM2.5 concentration—a measure of the most dangerous tiny airborne particles—soared to more than 40 times the World Health Organization’s annual guideline level on October 22, 2025. This spike in pollution, while not unprecedented, arrived with a sense of déjà vu for locals, who endure these hazardous conditions year after year, especially during the winter months. The causes are well-known: a toxic cocktail of vehicle emissions, industrial activities, the burning of crop residues in surrounding states, and, crucially, the widespread use of fireworks during Diwali, the Hindu festival of lights.
Despite efforts to curb pollution in recent years—including a 2020 ban on the manufacture, sale, and use of firecrackers in New Delhi—the Supreme Court of India this year eased a five-year ban, allowing so-called "green fireworks" for six hours on two festive days. These green fireworks, according to experts cited by BBC, are only 20-30% less polluting than traditional ones, still releasing harmful particles into the air. Enforcement of restrictions was lax: as residents told CNN and India Today, firecrackers were set off well beyond the permitted hours, and non-green firecrackers were still available in parts of the city. "Year on year, it goes from bad to worse," lamented Anushka Singh, a Delhi resident, who described how her throat became scratchy and her eyes burned after Diwali night. "Living in Delhi is a pain… I just wish that given the decades of data we would at least have stricter rules, ones that are actually implemented."
Others, like Chandra Tandon, acknowledged the cultural importance of bursting crackers but admitted, "I was breathing in those fumes throughout and it’s definitely not good. It would be good if we left the crackers burning to the kids… So, adults at least should do their part." The sentiment was echoed by many across the city, torn between tradition and the growing health crisis.
Yet, perceptions of the air quality varied widely. As India Today Digital reported, some Delhi-NCR residents felt the morning after Diwali was cleaner than the previous year, pointing to better visibility or less intense smog. Gaurav, from West Delhi, noted clearer skies, while others in East Delhi and Kalkaji described the air as "too bad" or complained of burning eyes and throat irritation. In Noida and Ghaziabad, some believed firecracker use was lower this year, though the air still felt heavy with pollution. However, the data told a different story: at 6 a.m. on October 21, Delhi’s PM2.5 levels reached 228 micrograms per cubic meter—15 times the WHO’s 24-hour limit. By 9 a.m., the city’s 24-hour average AQI was 356, and Delhi’s average AQI between October 20-21 was a staggering 429, worse than notoriously polluted cities like Lahore and Karachi, according to live data from a Swiss air quality company.
Why the disconnect between perception and reality? Scientists explained that weather conditions played a significant role. On Diwali night, the temperature in Delhi-NCR hovered between 23 and 25 degrees Celsius—the warmest in five years for the festival. Meteorologist Gufran Beig told India Today, "When the temperature is warmer, air movement is faster, and there is relatively less moisture in the air. So dispersion is very fast." Higher temperatures promote vertical mixing in the atmosphere, allowing pollutants to rise and disperse, which may have led some residents to believe the air was cleaner than it was. Still, wind speeds were low, and humidity levels fluctuated, sometimes trapping pollutants near the ground and creating dense haze. Habituation also dulled some residents’ sensitivity to pollution spikes, especially those living near constant sources like landfills.
The debate over the main culprits behind Delhi’s pollution raged on. According to BBC, the burning of crop residues—stubble burning—in Punjab and Haryana is a recurring problem, especially in winter. While some reports claimed a 77% decrease in stubble burning in 2025 due to devastating floods, official Punjab data showed a threefold increase in such fires in the ten days leading up to October 23. The number of crop residue fires in Punjab did fall from 36,663 in 2023 to 10,909 in 2024, but burning remains a cheap, quick way for farmers to clear fields. Delhi’s Environment Minister, Manjinder Singh Sirsa, accused Punjab officials of "forcing farmers to burn stubble" to worsen air quality near the capital. The Aam Aadmi Party, which governs Punjab, fired back, accusing the Delhi government of "lies about pollution" and "playing with people’s lives." Despite the finger-pointing, experts like Gufran Beig said that in 2025, the contribution of stubble burning to Delhi’s pollution was negligible—just 1 to 2%—and that fireworks were the main driver of the post-Diwali pollution spike.
Meanwhile, the Delhi government pressed ahead with new solutions. On October 23, 2025, the city conducted a successful trial for artificial rain through cloud seeding, a project jointly developed with the Indian Institute of Technology (IIT) Kanpur. The first full-scale operation is likely on October 29, aiming to use artificial rainfall to bring down particulate pollution during the smog season. This innovative approach comes after years of attempts to clean up Delhi’s air—sprinkling water on roads, odd-even vehicle restrictions, and the construction of costly smog towers in 2018—have yielded limited results due to inconsistent enforcement and coordination, as CNN noted.
Experts widely agree that systemic, long-term solutions are needed. These include broader deployment of field-cleaning technologies to reduce crop burning, stricter and better-enforced regulation of fireworks, and continuous air-quality monitoring, especially in the colder months when pollution tends to spike. As Delhi, Kolkata, and Mumbai all ranked among the world’s most polluted cities on October 22, 2025, the urgency for effective action has never been greater. For now, residents brace for more days behind masks, hoping that a combination of science, policy, and public will can finally clear the air.
The battle for Delhi’s skies is far from over, but with new technologies on the horizon and growing public awareness, the city’s fight against pollution may yet turn a corner—if all sides can come together and act decisively.
