New Delhi - More than a million private cars were banned from New Delhi's roads on Friday, as authorities began trialling drastic new measures to cut smog in the world's most polluted capital.
From 8:00 am on January 1 cars with odd-numbered licence plates will only be allowed on the roads on odd-numbered dates and those with even-numbered plates on the others, except on Sundays when the rule will not apply.
The restrictions will run until January 15 on a trial basis and are part of a wider drive aimed at reducing pollution levels that also includes shutting some coal-fired power plants and vacuuming roads to reduce dust.
The Delhi government says they could be introduced on a more permanent basis if they are a success, with Chief Minister Arvind Kejriwal promising that he and his ministers would car-pool.
"This plan will only be successful when it becomes a very big movement, when people will want to obey it from their heart," he said as he urged Delhiites to co-operate.
"Don't do it because Kejriwal says so, don't do it because the government is forcing you. Do it because you feel it is important for your life, your health."
Kejriwal's government announced the measures early December, responding to public pressure to tackle pollution levels more than 10 times the World Health Organisation's safe limits.
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.
Just under three million of these are private cars or vans, and another 1,400 are added every day.
The city has been shrouded in a toxic blanket of smog in recent weeks as winter sets in and cooler temperatures trap pollutants in the atmosphere, pushing harmful PM 2.5 levels sky-high.
These fine particles less than 2.5 micrometres in diameter are linked to higher rates of chronic bronchitis, lung cancer and heart disease after settling into lungs and pass into the bloodstream.
Some critics warn the plan could fail in a city where traffic rules are already routinely flouted, with even the federal environment minister calling the move "crazy".
Many believe Delhi residents will deploy the famed Indian skill of "jugaad" - creating a cheap alternative solution - by forging number plates or buying second cars.
Others expressed scepticism that the scheme would be successful given the large number of exemptions, which range from motorcycles to women driving alone. Campaigners say motor bikes create up to 31 per cent of total vehicular pollution.
To ensure compliance, traffic police and 10,000 volunteers will fan out across the city and violators will be fined 2,000 rupees ($30) - steep for the average Delhiite.
Delhi's government has hired 3,000 private buses to provide shuttle services into the city from residential areas to cope with the extra ridership.
Schools have been ordered to remain closed until the trial ends so that their buses can be pressed into action.