Drivers of the most polluting vehicles face an extra daily charge for driving into central London under a scheme introduced Monday that aims to improve air quality in one of Europe's most polluted cities.

London Mayor Sadiq Khan claimed that with the rollout of the new weekday "toxicity charge" -- dubbed the "T-charge" -- London had "the world's toughest emission standard".

The £10 (11.2-euro, $13.2) levy is in addition to a daily £11.50 congestion fee, and follows an order by the European Union for Britain to cut air pollution.

Khan, who announced the charge in February, said he was "determined to take urgent action to help clean up London's lethal air".

"The shameful scale of the public health crisis London faces, with thousands of premature deaths caused by air pollution, must be addressed," he said.

The levy applies to all petrol and diesel cars registered before the introduction of environmentally-friendly Euro 4 emissions standards in 2005.

But Transport for London, which runs the scheme, has said any vehicle registered before 2008 may be liable.

It estimates 6,500 vehicles per day will be covered, about 6.3 percent of around 103,000 that enter the congestion zone.

Even before it came into force, the charge has had a deterrent effect -- Khan said there has been a 15 percent reduction in eligible vehicles entering the area since the scheme was announced.

The European Commission in February issued a warning to five member states including Britain, urging them to take action on car pollution or risk being sent to the European Court of Justice.

It said that "persistently high" levels of nitrogen dioxide caused 70,000 premature deaths in Europe in 2013.

The mayor's office said 7.9 million Londoners lived in areas that exceeded World Health Organization guidelines on toxic air quality.

- 'Easy targets' -

The RAC, a British motoring group, said the mayor was right to take action over the oldest vehicles, "because these are more likely to be the most polluting."

But roads policy spokesman Nick Lyes warned that "drivers may also see themselves as an easy target".

London drivers appeared divided by the plans.

"I think it's a good thing (to) keep the air pollution down," said Tony Smith, 53, a waste removal driver whose modern vehicle is unaffected by the new charge.

But George Tamale, 36, a parcel delivery driver also not impacted by the T-charge, said he questioned the motives behind it.

"They just want people to buy new cars. It's not about the environment, it's about economics," he said.

London is the largest city around the world to use congestion charging, alongside Stockholm, Milan and Gothenburg.

Singapore was the first and now has the most comprehensive road-pricing system, which it plans to upgrade in 2020 by incorporating GPS technology.

Long-stymied plans for congestion charging in New York saw fresh impetus in August after state governor Andrew Cuomo came out in support of the idea for parts of Manhattan.

Studies of the London scheme indicate the number of cars entering the city centre has fallen by nearly a quarter since 2000.

But congestion remains a persistent problem, alongside poor air pollution.

Other measures city officials have tried recently include a trial of increased parking charges for diesel vehicles in the central borough of Westminster.

The new fee applies to the same area as the congestion charge zone, which was first introduced in 2003 and covers 21 square kilometres (8.1 square miles) of the city centre, on weekdays between 7am and 6pm.

The latest levy is intended to prepare Londoners for the introduction of an Ultra-Low Emission Zone across the city centre from April 2019, under the mayor's plans.

Source: AFP