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London is one of the most congested, and polluted cities in Europe.

Londoners were introduced to a congestion charge in 2003, forcing motorists to pay extra when they enter central London.

The move had some impact on traffic levels, but in July 2010, authorities introduced a new scheme, in an effort to get more people out of their cars.

Al Jazeera's Barnaby Phillips reports from London.

Source: Al Jazeera