More than a billion people celebrated Diwali in India on Monday, with the northern city of Ayodhya setting a new world record for the largest number of oil lamps lit at a single location. The Uttar Pradesh state government-backed Deepotsav event saw 2,617,215 clay lamps illuminated on the eve of the main festival, marking the return of the god-king Rama to his birthplace after 14 years of exile.
However, the celebrations were marred by severe air pollution in the capital, New Delhi, which was shrouded in a thick, toxic haze. Levels of PM2.5 reached 248 micrograms per cubic metre in parts of the city, more than 16 times the World Health Organisation's recommended daily maximum. By Monday afternoon, the air quality index (AQI) hit 500 in some areas, classified as 'severe', with expectations of further deterioration overnight.
The pollution spike is an annual phenomenon linked to firework use during Diwali, combined with the onset of winter smog and stagnant air trapping emissions from traffic and crop burning. Last year, AQI levels exceeded 1,000, forcing flight cancellations due to poor visibility. In response, the Delhi administration has invoked emergency measures under the graded response action plan (GRAP) and is planning to trial cloud seeding this month to trigger rain.
Despite a Supreme Court ruling allowing only limited use of 'green fireworks' on Diwali day and its eve, illegal fireworks remain a problem. The court noted that a blanket ban imposed seven years ago had been ineffective, as contraband continued to be smuggled into the capital. Experts have described cloud seeding as a temporary fix for the chronic issue of air pollution, which cuts life expectancy in Delhi by an average of 11.9 years compared to WHO guidelines.
Diwali, also observed by Sikhs, Jains and Buddhists, celebrates the victory of good over evil. Traditions vary by region, from early morning oil baths in the south to worshipping the goddess Lakshmi in the north. The festival is marked by lights, fireworks, feasting, new clothes and prayer, but the environmental cost continues to raise concerns.
