Authorities in the French capital Paris will restrict who can drive for a third day on Thursday, and they will allow people to ride public transportation in the city and its suburbs for free as an incentive to get them out of cars.  This is because air pollution levels stubbornly remain high.

Paris Mayor Anne Hidalgo tweeted a photo of the top of the Eiffel Tower peaking out from underneath a grey shroud over the city.  For several days recently, the level of PM 10 pollution has been higher than the recommended 80 micrograms per cubic meter, reaching 146 micrograms per cubic meter last Thursday.  The cold weather has people turning on their furnaces and lighting up stoves and fireplaces - but an anticyclonic weather system is trapping all of that noxious crap in the city's air.

So:  Cars with odd-numbered plates were banned on Tuesday, followed by even-numbered plated on Wednesday; they'll continue to alternate as long as the need exists.  The vehicle bans have only been introduced four times in the last two decades; once in 1997, but once each year since 2014.

"Without it the air would be even more polluted.  It's an emergency solution to an urgent problem," said Charlotte Songeur of the Paris air quality agency Airparif.  "Even before this, 1.6 million French people were breathing in a level of nitrogen dioxide over European recommended levels," she added.

One of the problems with the plan is catching all of the scofflaws.  Paris police handed out more than 1,700 traffic fines on Tuesday alone, suggesting the number of drivers ignoring the ban was even higher.  Since the fine is only about AU$33, the risk is apparently acceptable.  I guess it's easier to pay than to think about the 48,000 premature deaths in France each year due to air pollution.

"It's now 40 years that we"ve had health problems linked to air pollution.  Organizations measuring air quality give the same reports each year," lamented Sebastien Vray, president of the group Respire (Breathe).  "What are we waiting for to bring in technological change?  Our carmakers have known for the last 40 years they can improve their engines with increasingly efficient technology and the state must better inform the public to help them change."

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.