Just weeks after Beijing declared its first red alert status and initiated emergency restrictions to combat dangerous smog levels, another of the world's most polluted capitals has implemented similar measures.

Delhi, the capital territory of India, has embarked upon a two-week trial designed to halve the number of privately owned cars on public roads. Under the scheme, four-wheeled vehicles with registration plates ending in odd numbers are prohibited from driving on even dates of the month, and vice versa.

The prohibition began last Friday, but authorities were particularly concerned about what would happen this Monday, as millions of workers returned to work after the New Year weekend.

"There were doubts about what would happen when all the offices opened," said Delhi Transport Minister Gopal Rai, as reported by Atish Patel at BBC News. "We are glad that people are following the rules."

Under the plan, privately owned cars banned from driving on a particular day must stay off the roads between 8am and 8pm daily, except on Sundays. The scheme will stay in effect until January 15, but already Delhi's government is reporting early success in terms of air quality levels.

"The first results of ambient air data collected by mobile units of the Delhi Pollution Control Committee on 24 locations across Delhi on the New Year Day show an encouraging trend of reduction in air pollution in both PM2.5 and PM10 categories," a government release stated. "The implementation of the plying of four-wheeled vehicles on an odd-even basis was received with warmth by the residents of the national capital on the first day, and results of the ambient air quality measurement prove their efforts will yield positive results."

Despite the official spin, it's been reported that many 2,000-rupee fines (US$30) have already been issued to those flouting the rules. Ravinder Singh, a Delhi traffic police constable, told Nida Najar at The New York Times that he had issued several fines, with most of those caught illegally driving claiming medical emergencies.

"If it's a genuine emergency, we can make it out from the face and tell if they're lying," he said. "This is New Delhi, where people will use all kinds of clout. Everyone will say they know someone in government."

There's also doubt as to how effective the scheme will be due to a large number of exemptions that may curb the environmental impact of the prohibition. As Najar explains:

"Women are allowed to drive any car any time of day, seen as a nod to safety in a city where women face dangers on public transit. Two-wheelers – motorcycles and scooters, which experts say made up the majority of the nearly 9 million vehicles on the road as of March in Delhi – are also exempt. Cars using compressed natural gas, and those belonging to senior government officials and judges, can be on the roads any day as well."

The restriction also appears to have caused some concern among locals who are unsure whether their plates ending in a 0 (zero) are considered to be an odd or even number. Mathematically, 0 is considered even, but in any case, Delhi's official car restrictions also stipulate this by lumping in 0 with 2, 4, 6, and 8.