Only Parisian plates ending with an odd number will be permitted on roads in and around France's capital on Monday. Depending on air quality forecasts, the measure could continue Tuesday, in which case only cars with plates ending in an even number would be allowed.

"Our core objective is to ensure public safety because we want to end this pollution," Environment Minister Philippe Martin told a news conference on Sunday, warning that the air quality would likely worsen on Monday.

Scientific research has showed that high smog levels have numerous negative effects on cities and their inhabitants. In February, Chinese scientists found the capital, Beijing, barely suitable for living owing to heightened levels of smog.

A contaminated capital

Over the weekend, Paris allowed riders to travel for free on public transport as a visible haze hung over the city's streets. The recent weeklong spell of unseasonably warm weather has exacerbated the problem.

European Environment Agency figures for last Thursday show 147 micrograms of particulate matter per cubic meter of air in Paris - compared with 114 in Brussels, 104 in Amsterdam, 81 in Berlin and 79.7 in London. Last fall, the agency found that 88 percent of people in the vicinity of major European cities were exposed to contamination levels above standards set by the United Nations. However, political opponents and car associations have criticized France's regulation, calling it tough to police and accusing the Socialist government of conceding to pressure from its Green coalition partners ahead of local elections in late March.

"This is impossible to enforce, stupid, and an attempt to win votes," Pierre Chasseray, president of the drivers' lobby 40 Millions d'Autombolistes, told French media Sunday.

'Responsibility and civic-mindedness'

Authorities will exempt electric and hybrid vehicles and cars with at least three people aboard. The city plans to deploy about 700 police officers to ensure compliance.

Prime Minister Jean-Marc Ayrault has acknowledged the difficulties that the alternate driving plan would cause for commuters, but in a statement added that "this extra measure is necessary," and called on motorists to show a "spirit of responsibility and civic-mindedness."

France introduced its last restricted driving scheme in October 1997 in response to pollution from heavy diesel fumes.

mkg/rc (Reuters, dpa)