<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The London Low Emission Zone (LEZ) is a traffic pollution charge scheme with the aim of reducing the tailpipe emissions of diesel - powered commercial vehicles in London . Only vehicles that do not conform to higher emission standards are charged, the others may enter the controlled zone free of charge . The low emission zone started operating on 4 February 2008 with phased introduction of an increasingly stricter regime until 3 January 2012 . The scheme is administered by the Transport for London executive agency within the Greater London Authority . </P> <P> The zone covers most of Greater London (with minor deviations to allow diversionary routes and facilities to turn around without entering the zone and the M25 motorway). The boundary of the zone, which operates 24 hours a day, 7 days a week, is marked by signs . The LEZ emissions standards are based on European emission standards relating to particulate matter (PM), which are emitted by vehicles, which have an effect on health . The following vehicles are not charged: </P>

What does low emission zone in london mean
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