Updated

Paris' Police authority is again cracking down on the city's rocketing air pollution with a 24-hour traffic-regulating scheme that aims to halve the day's emissions from road vehicles.

Police say that on Tuesday only vehicles with an even-numbered license plate will be allowed to use the roads in Paris and its nearest suburbs. A hundred and forty checkpoints around the city will root out any odd-numbered cars and turn them back.

All day, public transport will be free to encourage its use.

The initiative is part of Mayor Anne Hidalgo's push to fight Paris' exceptionally high pollution and make the city more friendly for pedestrians and cyclists.

The scheme has been implemented twice before, in 2014 and 2015, sometimes affecting odd-numbered vehicles and sometimes even-numbered ones.