Paris was smothered Wednesday by its worst winter pollution in a decade, with commuters enjoying free public transport and half of all cars ordered off the road to try to clear the air.

The surge in pollution has been driven by cold weather and near windless conditions that have trapped exhaust fumes, smoke from wood fires and other pollutants, according to the French capital's AirParif air monitoring service.

Although bad by Paris standards, current levels of fine airborne particles, or PM10, are around 60 percent of those in Beijing and a fraction of readings in New Delhi, the world's most polluted capital. 

City authorities announced traffic restrictions would be extended to Thursday, with a ban imposed on private cars with registration plates ending in odd numbers from between 5:30 am (0430 GMT) and midnight. 

The rule has been in place since Tuesday, alternating between odd and even plates.

Public transport in the city was free for a second day running Wednesday, to encourage commuters to leave their vehicles at home, while school children were prevented from exercising outside.

"It's not the best time to be doing sport, that's clear," said David Ettinger, a 42-year-old teacher who uses the city's Velib cycle-hire service.

Mohamed Navhit, 29, a tricycle rickshaw driver plying his trade outside the Louvre, said he had been struggling with the air quality.

As a smoker, he noticed the deterioration, he said. 

"It feels like I'm smoking 10 cigarettes instead of one."

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

- Fines for motorists -

For more than a week now, PM10 readings have been at dangerously high levels of over 80 microgrammes per cubic metre of air particles, reaching 146 microgrammes/m3 last Thursday. 

Other parts of France are also being choked by smog.

Officials in the southeast Rhone valley region said they would introduce measures to restrict car use from Friday to combat the problem in the city of Lyon.

The Greens candidate in next year's presidential election, Yannick Jadot, said politicians needed to target the most polluting vehicles and restrict the use of diesel engines.

"We have politicians who tell us they are looking after our health," Jadot said. "The reality is that when they have to choose between traffic, diesel and our health, unfortunately they don't choose our health."

Measures are already in place to phase out diesel engines in buses in the capital.

This is only the fourth time Paris has resorted to traffic restrictions to cope with air pollution. The region's officials took similar measures in 1997, 2014 and 2015.

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

On Tuesday, traffic police were kept busy trying to enforce the anti-pollution measures, fining more than 1,700 motorists for flouting the order to leave their car at home.

A power failure at one of the city's main stations, the Gare du Nord, added to the transport pressures on Wednesday.

Trains to London, Brussels and Amsterdam came to a halt for several hours and intercity and local services were disrupted. 

On Tuesday morning, the main rail link from central Paris to the city's main airport, Charles de Gaulle, was knocked out of action after an accident brought down power lines.

State rail company SNCF said it hoped to have the line repaired by later Wednesday.

Source: AFP