India's capital has been shrouded in a toxic blanket of smog in recent weeks as cooler temperatures trap pollutants in the atmosphere, pushing harmful PM 2.5 levels sky-high. On January 1, 2016, pollutant levels in Delhi hit a 'hazardous' 429 on the US embassy's air quality index, meaning everyone is at risk of respiratory problems and children and older people should stay indoors.
As authorities began trialing drastic new measures to cut smog in the world's most polluted capital, more than a million private cars were banned from New Delhi's roads on Friday, January 1, 2016.
For 15 days from January 1, 2016, only cars with odd-numbered license plates will be allowed on the roads on odd-numbered dates and those with even-numbered plates on the other days to try to reduce pollutant levels which regularly hit 10 times the World Health Organization safe limits.
Hundreds of traffic police and volunteers took to the streets to enforce the scheme including dozens of children wearing smog masks and holding banners urging drivers to comply.
"Delhi has done it! Reports so far very encouraging," tweeted the city's Chief Minister Arvind Kejriwal, who said he was carpooling with colleagues to get to work.
One early violator caught driving a car with an even-numbered license plate on a busy stretch of road was fined 2,000 rupees ($30) and ordered to return home.
"I would have expected to catch at least dozens in the first half an hour, but surprisingly most people are obeying," said Ankit Kumar, a traffic policeman.
The restrictions, which run until January 15, 2016, on a trial basis, are part of a wider drive aimed at cutting air pollution that also includes shutting some coal-fired power plants and vacuuming roads to reduce dust.
Schools have been ordered to remain closed for the period so that their buses can be used to ferry commuters to work.
The Delhi government says the measures could be introduced on a more permanent basis if successful, although some believe city residents could try to get around the restrictions by forging number plates or buying second cars.
The scheme will be truly tested on Monday, when millions of commuters will have to find alternative ways to get to work after the long New Year weekend.
Many residents said that they were willing to do their part.
"We are ready to travel in public transportation as long as there aren't any hassles. Pollution is a real health concern and we have to do something," said Pallavi Agarwal, a 37-year-old doctor, as she stepped out of her SUV with her four-year-old son and husband.
Yet critics say the restrictions do not go far enough, with motorcyclists and women driving alone exempt. Campaigners say motorbikes create up to 31% of pollution from vehicles.
Others remain sceptical that drivers will observe the restrictions for long.
"Just wait for Monday, people are going to be back to their old habits. Delhiites are too used to their cars," said Kirti Lal, who commutes by bus.
A 2014 WHO survey of more than 1,600 cities ranked Delhi as the most polluted, partly because of the 8.5 million vehicles on its roads.
Car sales are soaring as incomes rise, with 1,400 extra vehicles pouring onto the city's already crowded roads every day.
JB Khatri, a 59-year-old auto-rickshaw driver, said he was enjoying the unusually light traffic. He said, "Every day we spend hours stuck in long jams and breathe in so much pollution, it makes us sick. This is a good change."
These fine particles less than 2.5 micrometers in diameter are linked to higher rates of chronic bronchitis, lung cancer and heart disease after settling into lungs and passing into the bloodstream.
On Friday the US embassy figures put PM 2.5 levels at 264 in Delhi, well above the WHO safe limit of 60.
In a measure of mounting concern, India's Supreme Court has recently ordered a temporary ban on large new diesel cars in Delhi and doubled a tax on diesel trucks.