Paris air pollution
© AFP/Getty ImagesToxic: Public transport was made free to encourage Parisians to leave their cars at home
Public transport has been made free in Paris for the second day running as authorities combat the worst winter pollution to hit the city in a decade.

AirParif, the French capital's air monitoring service, said pollution had spiked amid cold weather and windless conditions which have trapped toxic pollutants such as car exhaust and wood smoke.

In response, trains, buses and the metro were made free to use on Wednesday as officials attempt to encourage Parisians to leave their cars at home.

A ban was also placed on private cars with registration plates ending with even numbers between 5.30am (4.30am GMT) and midnight.

On Tuesday, the same restrictions were in place but for licence plates that ended in odd numbers.

The measures have previously been used in notorious pollution-hit cities Beijing and Delhi.

Schoolchildren have also been prevented from exercising outdoors while the alert remains in place.

Airparif has published readings of PM10 emission levels at more than 80 microgrammes per cubic metre of air particles for more than a week, which has triggered the pollution alert.

Karine Leger, of AirParif, told AFP news agency: "This is a record period of pollution for the last 10 years."

The restrictions are the fourth time Paris has introduced measures to cope with air pollution after action was taken in 1997, 2014 and 2015.

However, a parliamentary report has poured doubt of the effectiveness of the constraints by arguing the most polluting vehicles are not targeted.

But a parliamentary report has questioned the efficacy of the restrictions, arguing that they do not target the most polluting vehicles.

On Tuesday, officials reported heavy congestion in and around the city during morning and evening rush hour despite the ban on some cars, AFP reported.