Mainstream WeeklyThe air quality index (AQI) in Delhi has deteriorated so sharply that a bench of the Supreme Court was forced to advise lawyers to argue their cases virtually rather than come in person to the court. Responding to a submission by a leading lawyer who stated that lawyers were forced to use face masks the court observed that even face masks were ineffective against such high air pollution levels.
With Delhi air pollution levels breaching the severe plus category in December 2025 recording an AQI of around 500 the maximum level that monitors can record (AQI of 0 to 50 are considered as a safe limit in India with minimal and no adverse health impacts) the Delhi government has set in motion stage 4 of the Graded Response Action Plan (GRAP-IV) by placing curbs on most non-essential construction and demolition activities, restrictions on plying of BS-III petrol and BS-IV diesel four-wheelers and holding of hybrid classes for school children to reduce emissions and congestion. Besides Delhi citizens especially children and senior citizens were advised to stay indoors. GRAP is an emergency response mechanism operating in the Delhi national capital region and indicates the actions needed corresponding to four categories of AQI levels. The Supreme court also directed the Punjab and Haryana governments to file a status report on the steps taken to tackle stubble burning which is another factor for aggravating air pollution in Delhi.
Vehicular pollution is a major source of air pollution in Delhi accounting for over 51.5 per cent followed by road and construction dust, industrial and power plant emissions. Other sources are agricultural stubble burning during the post-harvest season in the neighbouring states of Punjab and Haryana and bursting of firecrackers during the Diwali festival.
Delhi has had a chequered history in tackling air pollution. Following the M C Mehta vs Union of India (1996) case the Supreme Court in 1996 directed the shifting of hazardous and polluting industries to out of Delhi. Thereafter in 1998 the court mandated the use of compressed natural gas (CNG) for public transport in Delhi and fixing the year 2001 as the upper time limit for this change over along with phase out of old vehicles and a ban on leaded petrol. Despite these measures a study by the Delhi-based Centre for Science and Environment (CSE) noted that air pollution levels had increased in the city due to an explosive growth of fossil fuel-based private vehicles, traffic congestion and inadequate expansion of public transport. One study suggests that more people die of air pollution than cancer in Delhi. In the recent years the only occasion when Delhi