People cross the Champs-Élysées as Paris suffers a pollution spike. (Michel Euler/AP)

PARIS — As the fabled City of Light faces its highest pollution levels in more than a decade, authorities have banned half of its drivers from city streets and made public transportation free to accommodate the overflow.

Experts say the unusually smoggy skies are a function of emissions from power plants, traffic and heating — particularly wood fires — kept closer to ground level by low winds and high pressure.


The Eiffel Tower is shrouded in haze as the sun comes up on Thursday. (Ian Langsdon/European Pressphoto Agency)

On Thursday, only cars with even-number license plates were allowed to drive, in an effort to limit traffic emissions. On Wednesday, only those with odd-number license plates were allowed. Public transportation has been free since Tuesday. It is the fourth time in 20 years that Paris has had to impose this sort of traffic ban in response to dangerous pollution levels. The free public transport is costing the city an estimated $4.3 million a day, according to the Local news outlet.

Anne Hidalgo, Paris’s Socialist mayor, has wasted no time in using the situation to underscore her long campaign against car emissions as a threat to public health. On Tuesday, she tweeted a picture of the Eiffel Tower, barely distinguishable beneath a widespread haze.

“Paris today. The proof that we need to reduce the presence of cars in the city,” she wrote.

Last week, Hidalgo reaffirmed her pledge to ban diesel vehicles from the French capital by 2025, in conjunction with other capital cities such as Athens, Madrid and Mexico City.

“Every year, 2,500 people die in Paris because of air pollution,” she said. “We cannot remain inactive in this situation.”

This is not the first time Paris has imposed such measures in response to high pollution levels, with similar traffic bans in 2015, 2014 and 1997.

Many drivers, though, have paid no attention to the traffic bans, and police issued approximately 1,700 fines on Tuesday, the Local reported.