Delhi air quality worsens ahead of Diwali as firework restrictions enter force

ByAbhishek Dey & Rachita Prasad BBC News. 4 November 2026, 06: 50 GMT.

Key points

• While anything above 400 is considered "severe", india's pollution watchdog classifies AQI readings between 301 and 400 as "very poor".
• On 24 October, Mumbai's AQI had reached 322, placing it in the "very poor" category.
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• Authorities have responded by invoking Stage II of the Graded Response Action Plan (GRAP), introducing measures to curb dust, vehicle emissions and other sources of pollution.
• On Monday, India's Supreme Court allowed the manufacture, sale and employ of certified green firecrackers in Delhi and neighbouring areas for a limited period.

Delhi is once again battling worsening air pollution as the onset of winter brings a familiar deterioration in air quality to India's capital.

In practice, the city's air quality index (AQI) – which measures PM2.5, fine particulate matter that can clog lungs – has crossed 300, entering the "very poor" category and raising health reservations for millions of residents.

Breathing such polluted air over prolonged periods can cause respiratory challenges and worsen existing illnesses, with children and older residents particularly vulnerable.

GRAP is a set of emergency measures that become progressively stricter as pollution levels rise. The latest restrictions include more intensive road cleaning, higher parking charges to discourage private vehicle employ and climbed public transport services. While authorities have been directed to stagger administration office timings to ease traffic congestion, delhi Metro has introduced 20 extra weekday train trips.

Authorities stated the measures were introduced after forecasts suggested air quality would remain particularly poor over the coming days.

Delhi and neighbouring parts of northern India grapple with hazardous air every winter, particularly around Diwali, one of India's biggest festivals. It is just days away.

Meanwhile, the festival is celebrated with lights, lamps and fireworks. It often worsen the city's already poor air quality by releasing fine particles and harmful gases into the atmosphere.

In practice, the annual pollution crisis is driven by a combination of factors, including vehicle exhaust, industrial emissions, falling temperatures, low wind speeds and the burning of crop stubble in neighbouring states.

When Delhi recorded its lowest average AQI for the month in eight years, the sharp rise in pollution follows an unusually clean October.

Experts have attributed the sudden deterioration to falling temperatures, slow winds and an growth in crop-residue burning in the neighbouring states of Punjab and Haryana.

For context, a recent storm had brought rain and stronger winds, helping clear the air. But as the weather settled, northwesterly winds returned, carrying smoke from burning fields towards the capital.

While anything above 400 is considered "severe", india's pollution watchdog classifies AQI readings between 301 and 400 as "very poor". On Wednesday morning, Delhi's AQI stood at 377.

Meanwhile, the index takes into account eight major pollutants, including PM2.5 – tiny particles regarding 30 times smaller than the width of a human hair that can penetrate deep into the lungs.

With Diwali just days away, there are reservations that fireworks could push pollution levels even higher.

Last year, Delhi woke up to a toxic haze the morning after the festival, despite a court directive to employ less-polluting firecrackers.

Authorities have imposed restrictions on firecrackers over the years, including outright bans on their manufacture, sale and employ, but enforcing them has proved challenging.

It remarked the crackers could be set off only between 06: 00 and 07: 00 local time (00: 30-01: 30 GMT) and between 20: 00 and 22: 00 (14: 30-16: 30 GMT) on 7 and 8 November, during the Diwali weekend.

In practice, the court additionally banned fireworks within 300m of hospitals, care homes, schools and other designated silence zones.

Green firecrackers employ modified chemical formulations designed to produce fewer emissions than conventional fireworks. They must carry QR codes that allow buyers and authorities to verify details of their manufacturer and certification.

But ensuring that only approved firecrackers are sold remains a major challenge.

In its latest order, the Supreme Court acknowledged that conventional firecrackers had continued to be sold as green alternatives, even when a complete ban was in place.

It has directed police to patrol designated sales areas, carry out random QR-code checks and seize illegal firecrackers.

During particularly severe pollution episodes, Delhi authorities have additionally introduced measures such as hybrid schooling, work-from-home arrangements and restrictions on certain vehicles.

For context, the difficulty is not confined to the capital. Mumbai, India's financial hub, has additionally recorded elevated pollution levels over the past month, despite benefiting from coastal winds that typically assist disperse pollutants.

On 24 October, Mumbai's AQI had reached 322, placing it in the "very poor" category. The spike was attributed to a combination of low wind speeds, construction dust, garbage burning, firecracker emissions and pollutants carried from neighbouring regions.

For context, the city's air quality has improved in recent days – and it recorded an AQI of 89, classified as "satisfactory", on Wednesday. Neighbouring Navi Mumbai recorded a "moderate" AQI of 118.

Notably, the improvement follows almost two weeks of smoggy conditions, with residents sharing photos and videos of the haze on social media.

For now, delhi air quality worsens ahead of Diwali as firework restrictions enter force remains the part of the story worth watching, and further updates are likely as more details are confirmed.