Like many middle-class professionals in this car-crazed capital, Tarun Thawani drives to work every day, both for comfort and because he usually has piles of documents to carry.
But on Monday, the accountant left his car and bulky briefcase at home and wedged into the back of a motorized rickshaw for his 10-mile commute as New Delhi tries to curb the use of private vehicles.
"It was inconvenient," said Thawani, 32. "But in the long term hopefully this will be something good."
The Indian capital is counting on cooperation from residents such as Thawani as it becomes the latest city to force cars off the road to reduce its air pollution, which by most measures now is the worst of any major city in the world.
For the first two weeks of the year, private cars with even-numbered license plates are allowed on the roads only on even-numbered dates, and those with odd-numbered plates on odd dates. The restrictions have noticeably reduced traffic in a city with 9 million cars, more than double that of a decade ago.
Like Beijing, Mexico City, Paris and other cities that have tried similar measures, officials in New Delhi describe the two-week trial as an emergency intervention to fight the capital's foul air, a dusky gray haze that makes visitors feel like they're wearing permanently fogged-up sunglasses.
In 2014, the World Health Organization found New Delhi's air to be the dirtiest of 1,600 cities it studied. Scientists blame the high levels of pollutants -- especially fine PM 2.5 particles measuring 2.5 microns across, which can burrow deep into the lungs -- for thousands of deaths a year.
The winter months are particularly noxious in Delhi, when smoke from wood fires, burning of agricultural land on the city's outskirts, fumes from diesel generators and dust from construction sites mix and settle above the low-lying capital.
Limiting vehicles alone is unlikely to improve air quality significantly, but supporters of the plan say it has helped raise awareness of the problem.
"Transport may be only a 15%-to-20% chunk of the problem at the moment, but it's the chunk we can address right away," said Bhargav Krishna, a researcher with the Public Health Foundation of India. "There's a recognition within the populace that some amount of personal action and responsibility is needed to address this issue."
After the Jan. 1 holiday and the weekend, Monday, the first full working day, marked the biggest test of the initiative.
City officials deployed 3,000 additional buses, many borrowed from public schools that have scheduled a two-week holiday as part of the trial. Thousands of traffic police, volunteers and hidden cameras were posted across the smoggy city to look for odd-numbered violators, who would be subject to $30 fines.
Officials and residents reported widespread compliance. Delhi officials carpooled, rode bikes or took public transit to work. Uber and other taxi apps encouraged customers to share rides.
Buses were jammed with passengers, but unlike normal days when they are stuck in traffic for long stretches, most were able to complete their routes. Experts hoped this would demonstrate the need to improve a public transit system that is plagued by overcrowding and a chronic shortage of buses.
"With more free-flowing traffic, the efficiency of buses, taxis and rickshaws has improved for the majority of the commuting masses," said Anumita Roy Chowdhury, executive director for research and advocacy at the Center for Science and Environment, a New Delhi think tank.
"That is the main solution that Delhi really needs and that should be sustained even after the odd-even program is over."
Delhi's chief executive, Arvind Kejriwal, has announced other measures to reduce pollution, including shutting down a heavily polluting power plant in the city, temporarily banning the sale of large diesel vehicles and ordering taxi companies to convert their fleets to compressed natural gas.
The experiences of other cities that have tried similar measures to reduce traffic have been mixed.
To clear up the freeways before the 1984 Summer Olympics in Los Angeles, employers implemented staggered work schedules while the city created temporary bus-only lanes and synchronized traffic lights to improve the flow of vehicles. Residents remember those two weeks as a traffic-free breeze, but the gridlock soon returned.
Beijing adopted an odd-even rule to clear its notoriously bad air ahead of the 2008 Olympics, and pollution levels dropped significantly. The city has since created other traffic rules for periods of bad smog.
Mexico City tried to ban cars for one day a week depending on their license plate number, but affluent residents responded by buying more cars, and pollution actually went up.
Critics of the New Delhi plan said there are too many loopholes. The city exempted motorcycles -- which experts say account for one-third of emissions from vehicles -- and is allowing women-only cars on the roads at any time.
With buses, taxis, rickshaws and certain government vehicles also exempt, experts said the odd-even plan takes aim at less than 10% of emissions.
According to IndiaSpend, an independent website that has installed air-quality monitors across the city, the concentration of fine pollutants remains at severely unhealthy levels. All the site's indicators for Delhi glowed dark red Monday evening, meaning average daily PM 2.5 levels were above 400 microns per cubic meter of air -- more than 10 times higher than the U.S. standard for what is safe.
"From the data we are looking at, there has not been any significant change" in the pollution levels, said Ronak Sutaria, chief architect of the initiative, dubbed #Breathe. "These things happen only over the very long term."
V.K. Jain, an accountant, owns one car with an odd-numbered plate and another with an even-numbered plate. On Monday, he left his Mercedes at home and drove his daughter-in-law's Hyundai hatchback to work.
"I don't know if the pollution has improved," Jain said, glancing at the drab sky as he folded himself into the hatchback to head home. "But the driving is definitely easier."