A general view shows the Eiffel tower and the Paris skyline through a small-particle haze March 13, 2014.
Philippe Wojazer—Reuters
March 14, 2014 11:38 AM EDT

A number of French cities including Paris have decided to make public transportation free this weekend in an effort to combat extraordinarily high levels of smog.

The emergency measure was announced by the French Minister for Ecology Philippe Martin on Thursday, AFP reports. The severe pollution is caused by unusually warm weather, a lack of wind, and a combination of cold nights and balmy days. Airparif, a non-profit organization accredited by the Ministry of Environment to monitor the air quality in Paris, reported that Thursday’s level of pollution hit the top of its index and that the agency will remain on alert over the next few days.

In October, the World Health Organization classified outdoor air pollution as carcinogenic.


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