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

Delhi is once again battling worsening air pollution as the onset of winter brings the capital its familiar seasonal deterioration in air quality. The city's air quality index, which measures PM2.5 fine particulate matter capable of clogging the lungs, crossed 300 on Wednesday morning, standing at 377. India's pollution watchdog classifies readings between 301 and 400 as "very poor", while anything above 400 is considered "severe". Prolonged exposure to such air can cause respiratory problems and worsen existing illnesses, with children and older people particularly vulnerable. In response, authorities invoked Stage II of the Graded Response Action Plan (GRAP), a set of emergency measures that tighten progressively as pollution rises. The latest restrictions include more intensive road cleaning, higher parking charges to discourage private vehicle use and increased public transport services. Delhi Metro has added 20 extra weekday train trips, and officials have been directed to stagger government office timings to ease congestion. Officials said the measures were introduced after forecasts suggested air quality would remain very poor in the coming days. The sharp rise follows an unusually clean October, during which Delhi recorded its lowest average AQI for the month in eight years. Experts attribute the sudden deterioration to falling temperatures, slow winds and increased crop-residue burning in the neighbouring states of Punjab and Haryana. A recent storm brought rain and stronger winds that briefly cleared the air, but northwesterly winds returned as the weather settled, carrying smoke from burning fields towards the capital. Vehicle exhaust, industrial emissions and Diwali fireworks add to the annual crisis, which grips Delhi and much of northern India every winter. With the festival just days away, concerns are growing that fireworks could push pollution levels even higher. Last year, Delhi woke to a toxic haze the morning after Diwali despite a court directive to use less-polluting firecrackers. Authorities have imposed restrictions over the years, including outright bans on the manufacture, sale and use of firecrackers, but enforcement has proved difficult. On Monday, the Supreme Court allowed the manufacture, sale and use of certified green firecrackers in Delhi and neighbouring areas for a limited period. It ruled they may be set off only between 06:00 and 07:00 local time and between 20:00 and 22:00 on 7 and 8 November, during the Diwali weekend. The court also banned fireworks within 300m of hospitals, care homes, schools and other designated silence zones. Green firecrackers use modified chemical formulations designed to produce fewer emissions and must carry QR codes allowing buyers and authorities to verify the manufacturer and certification. However, the Supreme Court acknowledged in its latest order 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. The problem is not confined to the capital. Mumbai recorded an AQI of 322 on 24 October, in the "very poor" category, despite coastal winds that typically disperse pollutants. Low wind speeds, construction dust, garbage burning, firecracker emissions and pollutants carried from neighbouring regions were blamed for the spike, which followed nearly two weeks of smoggy conditions. Air quality has since improved: on Wednesday Mumbai recorded an AQI of 89, classified as "satisfactory", while neighbouring Navi Mumbai registered a "moderate" 118. During particularly severe pollution episodes, Delhi authorities have previously introduced hybrid schooling, work-from-home arrangements and restrictions on certain vehicles.