ROME: Rome, one of Europe's most traffic-clogged cities and home to thousands of ancient outdoor monuments threatened by pollution, plans to ban diesel cars from the centre by 2024, its mayor said.

Virginia Raggi announced the decision on her Facebook page on Tuesday, saying: "If we want to intervene seriously, we have to have the courage to adopt strong measures".

Her comments followed a court ruling in Germany that cities there can ban the most heavily polluting diesel cars from their streets.

About two-thirds of the 1.8 million new cars sold in Italy last year were diesel, according to industry figures.

Rome has no major industries, so nearly all of the air pollution in the Italian capital is caused by motor vehicles.

The city regularly tries to ban older, more polluting vehicles from roads on days when pollution reaches critical levels.

It has also tried to reduce pollution by allowing only cars whose number plates end in either odd or even numbers to circulate on alternate days.

But both regulations are widely flouted and lightly enforced by traffic police. To skirt the alternate days regulation, many families buy a used car with a different number plate.

Apart from health issues, pollution from combustion engines causes severe damage to Rome's many ancient outdoor monuments.

According to a study last year by a branch of the culture ministry, 3,600 stone monuments and 60 bronze sculptures risk serious deterioration because of air pollution.

Ahead of celebrations marking the start of the new millennium in 2000, the darkened facade of St. Peter's Basilica at the Vatican was cleaned as part of a project that lasted several years.

But fresh signs of pollution-related stains are visible again.

Before the German court's ruling on Tuesday, officials in highly industrialised Milan, in northern Italy, had already announced plans to make the city diesel free by 2030.

(Reporting by Philip Pullella Editing by Mark Potter) ((philip.pullella@thomsonreuters.com;))