- 10 updates
Boris Johnson has announced a revolution to improve the capital's air quality.
If it went ahead it would be the biggest change to London's roads since the Congestion Charge came in a decade ago.
The Mayor wants what's called an "ultra-low emission zone" by 2020 - banning cars, buses or lorries that don't have low or zero emission engines.
But will the technology and the money be ready for such a bold plan in just seven years?
Our Political Correspondent Simon Harris reports.
All vehicles driving in central London during working hours will have to be zero or low-emissions, under new plans for an ultra-low emissions zone.
The Mayor of London made the announcement this morning, and says he wants his plans in place by 2020.
Our political correspondent Simon Harris reports.
Simon Birkett, founder of the Clean Air in London campaign, says the plans are being scheduled five years too late.
He's urging Boris Johnson to introduce the ultra-low emission zone in 2015, rather than 2020.
Mayor of London Boris Johnson speaks to ITV News about his plans for an ultra-low emission zone.
The Green Party has published this picture, claiming that is shows "why we need a very low emission zone for central London ASAP, not in 2020".
It is a map of nitrogen dioxide (NO2) pollution in the congestion charging zone, put together by Assembly Member Jenny Jones.
It is based on NO2 emissions modelling carried out by Kings College London, not on actual readings.
The ultra-low emission zone is expected to be based on the current Congestion Charge map.
The Green Party says that London has been breaking European air pollution limits for nitrogen dioxide since 2010.
London Assembly Member Jenny Jones welcomed the announcement of an ultra-low emission zone - but urged the mayor to move much more quickly.
Boris Johnson says he intends to introduce the ultra-low emission zone from 2020.
By that time, City Hall says, all central London buses will be hybrid vehicles, zero-emission taxis will be running on the capital's streets, low-emission options for freight will be available and electric cars may be in far greater use.
The Mayor says his proposal will act as a challenge for car manufacturers to develop more affordable low-emission vehicles.
Our Political Correspondent Simon Harris is tweeting from a press conference on traffic congestion and air pollution at City Hall.