London has won an award for its "leading role" in green transport initiatives and the congestion charge.
TfL said traffic in the city has fallen by 21% since 2003
US-based Institute for Transportation and Development Policy (ITDP) named London and Paris as joint winners of the 2008 Sustainable Transport Award.
The ITDP praised London's congestion charge saying it has become a "model for the world".
London Mayor Ken Livingstone said the award recognised the city's "decisive action to reduce traffic congestion".
The city was praised for the levy which led to a 21% fall in traffic since its introduction in 2003, Transport for London (TfL) said.
The panel also highlighted the 45% increase in bus passengers in London and a 43% rise in cyclists.
Mr Livingstone said: "This award recognises London's leading role in taking decisive action to reduce traffic congestion and improve the environment.
"We will be making the whole of Greater London a Clean Air - Low Emission Zone from 4 February, effectively banning the most polluting lorries from our roads," he said.
Peter Hendy, London's Transport Commissioner, said: "London has seen a five per cent shift away from the car to public transport, walking and cycling.
"TfL is continuing to advise many world cities on how to tackle congestion, improve public transport, and introduce sustainable transport solutions for growing cities," he said.