India’s capital Delhi is facing another worsening air pollution crisis, with its air quality index (AQI) climbing to 377 as winter approaches and concerns grow over the impact of upcoming Diwali celebrations.
The reading recorded on Wednesday morning places the city firmly in the “very poor” category, raising health concerns for millions of residents.
Prolonged exposure to polluted air can trigger respiratory problems and aggravate existing illnesses, with children and older people particularly vulnerable.
In response, authorities have activated Stage II of the Graded Response Action Plan (GRAP), introducing additional restrictions to tackle dust, vehicle emissions and other pollution sources.
The measures include more frequent road cleaning, higher parking charges to discourage private vehicle use and an expansion of public transport services.
Delhi Metro has added 20 weekday train trips, while government departments have been instructed to stagger office timings to reduce traffic congestion.
Officials said the measures were necessary after forecasts indicated that air quality would remain in the “very poor” category over the coming days.
The deterioration comes just days before Diwali, one of India’s biggest festivals, when millions celebrate with lamps, lights and fireworks.
Firecrackers release fine particulate matter and harmful gases, potentially worsening the already polluted air. Last year, Delhi was covered in a toxic haze the morning after the celebrations, despite a court directive encouraging the use of less-polluting fireworks.
The city’s annual pollution crisis is driven by several factors, including vehicle exhaust, industrial emissions, falling temperatures, weak winds and the burning of agricultural stubble in neighbouring states.
Delhi had recorded its lowest average AQI for October in eight years, but conditions deteriorated sharply following a change in weather patterns.
Experts attributed the latest pollution spike to falling temperatures, slower winds and increased crop-residue burning in Punjab and Haryana.
A recent storm had temporarily improved air quality by bringing rain and stronger winds. However, as weather conditions stabilised, northwesterly winds returned, carrying smoke from burning agricultural fields towards the capital.
India’s pollution authorities classify AQI readings between 301 and 400 as “very poor”, while readings above 400 are considered “severe”.
The index measures eight major pollutants, including PM2.5, tiny particles approximately 30 times narrower than a human hair that can penetrate deep into the lungs.
With Diwali approaching, further deterioration is feared as fireworks add to the pollution burden.
India’s Supreme Court has repeatedly imposed restrictions on firecrackers, including bans on their manufacture, sale and use, although enforcement remains a major challenge.
On Monday, the court permitted the manufacture, sale and use of certified green firecrackers in Delhi and surrounding areas for a limited period.
The approved fireworks may only be used between 6am and 7am, and from 8pm to 10pm, on November 7 and 8 during the Diwali weekend.
Fireworks are also prohibited within 300 metres of hospitals, care homes, schools and other designated silence zones.
Green firecrackers use modified chemical formulations intended to produce fewer emissions than conventional fireworks. Each approved product must carry a QR code allowing buyers and authorities to verify its manufacturer and certification.
However, the Supreme Court acknowledged that conventional fireworks had continued to be marketed as green alternatives despite existing restrictions.
It has directed police to patrol designated sales areas, conduct random QR-code inspections and seize illegal products.
During particularly severe pollution episodes, Delhi authorities have also resorted to measures such as hybrid schooling, work-from-home arrangements and restrictions on certain vehicles.
The pollution problem is not limited to Delhi. Mumbai, India’s financial capital, has also experienced elevated pollution levels in recent weeks despite its coastal winds, which usually help disperse pollutants.
On October 24, Mumbai’s AQI climbed to 322, entering the “very poor” category.
The spike was attributed to weak winds, construction dust, garbage burning, firecracker emissions and pollution drifting in from neighbouring regions.
However, conditions have improved in recent days. Mumbai recorded an AQI of 89, classified as “satisfactory”, on Wednesday, while neighbouring Navi Mumbai registered 118, placing it in the “moderate” category.
The improvement follows almost two weeks of smoggy conditions, which prompted residents to share photographs and videos of the haze on social media.
