For nearly a week now, France has been on "pollution alert" and while many cities have taken drastic action, Paris went on step further - restricting drivers' car use to every other day.
On Monday, Parisians' car licence plates determined whether they were allowed to hit the roads – with only odd numbers allowed to circulate the city. Free public transport was extended to accommodate people owning cars with even-numbered licence plates.
The measure was announced by the government on Saturday after warnings that Paris would see critical levels of air pollution on Monday, and marks the first time since 1997 that such a measure was introduced.
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It comes after an air pollution alert for the region was raised on March 7 by Airparif, an independent association that measures air quality around France. Its pollution index for Paris stood at 75 on Monday – where 0 marks "very low" air pollution and 100 marks "very high."
The recent air pollution stems from "anticyclonic" conditions, during which cold nights were followed by much warmer days, preventing air pollutants to scatter in the normal way.
Last week, Paris called on its inhabitants to ditch their cars and announced free residential parking and electric car (Autolib') and bike sharing (Velib) services for the duration of the alert.
The move was welcomed by Parisiens, with the use of both Autolib' and Velib' soaring. By the end of last week, Velib' reported a 130 percent hike in usage, while Autolib's was 37 percent higher.
But efforts to curb the pollution problem do not come cheap. Jean-Paul Huchon, president of the Ile-de-France region - which includes Paris and 22 other municipalities that have introduced the alternative driving measures - told AFP the move was costing the region 4 million euros ($5.5 million) per day.
So far, however, it appears to have been relatively successful.
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The region's police force said that the measure had reduced congestion in the city by 60 percent on Monday. The police added that by midday, it had issued 3,859 fines to those not respecting the measure – but told AFP this number was relative low, "considering normal traffic in Paris."
A number of cars were exempt from the measure, including electric cars, emergency vehicles and cars transporting at three or more people.
French car-sharing website Blablacar told CNBC that the website had seen a surge in carpool demand following the government's announcement of the alternate traffic measure.
"Car-sharing for short journeys, from home to office remains very rare in France," spokesperson Laure Wagner said. However by Sunday evening, the company had registered a 30 percent increase in car-share offers and a 70 percent rise in demand for car-shares.
"People organized themselves by Sunday, but we could see an imbalance between offer and demand," Wagner said. She added that the majority of journeys offered were from suburb to suburb, as "those that go to Paris have the possibility of taking public transport."
On Monday afternoon, the French minister for ecology Philippe Martin said the alternative traffic measure would not be repeated on Tuesday.
"Results from the measures already taken and in accordance with forecasts we can make, the Prime Minister has taken the decision to not renew the alternate driving measure tomorrow, Tuesday," he said in a press conference.
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