By David Willey in Rome

Italians are being forced to leave their cars at home on Sundays for the next few weeks.

The use of private cars has been banned in more than 150 towns and cities in an attempt to reduce atmospheric pollution and to encourage the use of public transport.

After successful experiments earlier this winter in Milan and Turin - both big industrial cities suffering from smog - the Sunday car ban has been extended to urban areas all over the country.

Ten major cities, including Rome, are closing off the whole city centre.

The car ban will last for 10 hours and public transport is free all day.

Admission to museums and archaeological sites is also free.

Each city is making its own rules. Some, including Palermo in Sicily, have already agreed to extend the ban until May.

The environment minister says he will analyse results before deciding whether to make carless Sundays a permanent feature in Italy.

In Milan, the amount of benzine and carbon dioxide in the atmosphere was reduced considerably by two consecutive Sundays without cars.

Surprisingly, in a country which has one of the highest rates of car ownership in the world, four out of five Italians say they are in favour of the Sunday car ban.

One of the main reasons for traffic congestion in Italian cities is inadequate public transport and one of the main aims of carless Sundays is to encourage more people to use buses, trams and the underground, where it exists.

But until public transport improves radically, most Italians are unlikely to leave their cars in the garage.