PARIS (Reuters) - The French capital Paris announced on Wednesday licence-plate based driving restrictions for a third day in a row and plans bans on old cars as the City of Light experienced the worst air pollution in a decade.

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On Tuesday and Wednesday, Paris banned cars from circulation based on whether their license plates ended with odd or even numbers. It will now ban half of all traffic again on Thursday.

Other French cities such as Lyon are also planning bans as clouds of pollution hang over many European cities due to a lack of the winds that normally blow in off the Atlantic Ocean.

It is only the fourth time in 20 years that Paris has imposed such a ban and the first time it applies for consecutive days. Municipalities around Paris also imposed the ban.

With its famous Eiffel Tower shrouded in a grayish haze and some Asian tourists donning face masks, the city also made all public transport, residential parking and the Velib’ bicycle and Autolib’ electric car schemes free.

“Cars are poisoning the air. We need to take preventive measures,” said Paris city hall transport official Herve Levife.

Besides instant measures like license-plate based driving bans, the city also plans to step up its fight against chronic pollution by gradually banning the oldest and most polluting vehicles from the city center, he said.

“We want these bans to automatically take effect when the pollution exceeds a certain level, not have to negotiate them with the government each time,” Levife added.

From mid-January, Paris will become the first French city to launch the new “Crit’Air” vignette system that will require all cars to have a color-coded sticker indicating their age and pollution level. The stickers will allow police to control which vehicles can circulate in the city center.

Grenoble in eastern France also plans to use the vignettes and other French cities are looking into banning clunkers from their roads.

Cars 20 years and older have already been banned from Paris roads from July 1, 2016 and some 120,000 stickers have been distributed. But participation in the scheme so far has been voluntary and enforcement scarce.

From July 1, 2017, the city will impose bans on diesel-powered cars and vans first put into circulation in 2001 and trucks first registered in 2006. Between 2018 and 2020, the city will gradually tighten circulation permits.

Paris has no plans to introduce London-style tolls for cars entering the city.

Paris Mayor Anne Hidalgo is on a drive to reduce car traffic. She has increased the cost of parking meters, banned free parking on Saturdays and the August holiday period, and is turning a highway on both banks of the Seine into a riverside park.