text: In source 2, "Paris bans driving due to smog," says Duffer. Paris enforced partial driving ban to clear the air. Duffer says, on Monday motorists even even-numbered licecnse plates were ordered to leave their cars at home or suffer a 22-euro fine ($31)." On the next day odd-numbered plates would do the same. Nearly 4,000 drivers suffered this fine. As of the 27 other peoples' cars were impounded for their reaction. "In the capital of France 60% congestion were down," explains Duffer. Days when was "cold at night and warm in the day were causing the warmer air to trap car emissions. Diesel fuel was blamed, since France has [] tax policy that favors diesel over fasoline," explains Duffer. Diesel  is 67% of vehicles in France, compared to 53.3% average of diesel engines in the rest of Western Europe, according to Reuters.