India's Supreme Court has come to the rescue of residents of the capital choking on a record level of pollution, ordering the government to come up with an emergency plan to tackle the problem in 48 hours.
The city has been in the grip of thick smog for several days since Deepavali, triggered initially by firecrackers let off during the festival. The problem has been exacerbated by the usual pollution caused by vehicles as well as farmers burning their crop stubble after the harvest in the neighbouring states of Punjab and Haryana.
The air quality generally worsens with the onset of winter in Delhi and the lack of wind now has not helped matters.
Separately, the National Green Tribunal - India's "green" court - yesterday ordered a ban on all construction in the Delhi capital region for a week and asked municipal bodies to divert half of their staff to carry out field inspections. It also criticised the authorities for not reacting quickly to the pollution build-up.
Pollution levels in Delhi, which has a population of over 25 million, have doubled over the past decade, with more cars on the road, construction activity, the growing number of polluting industries in nearby areas and crop fires.
The concentration of PM2.5 - the fine particles linked to higher rates of chronic bronchitis, lung cancer and heart disease - was at a "hazardous" level of 372 yesterday, according to the American Embassy. But the number was lower than Monday's stratospheric reading of 762 in some parts of the capital.
Levels between 301 and 500 are classified as "hazardous", meaning everyone faces a risk of respiratory effects and should stay indoors, while levels above 500 are beyond the official index.
People have complained of a burning sensation in their eyes and shortness of breath.
Experts said there was definitely a need for better coordination among the federal and state governments. "You need emergency action when smog reaches a critical level," said Centre for Science and Environment executive director Anumita Roychowdhury.
The Delhi authorities have so far responded to the smog by including a ban on setting off firecrackers except at religious events. Schools have been shut since Monday, all construction work has been banned for five days and a coal- fired power plant has been temporarily closed. The authorities are also reported to be considering cloud seeding to produce rain.