The group, known as Reclaim the Streets, says the blockade is to enforce the advice given to motorists by the Department of the Environment to leave their cars at home and use public transport. Rising levels of traffic fumes and the strong sunlight have combined in recent weeks to produce a noxious cocktail of irritant gases. Ozone, which can trigger asthma attacks and damage crops, has proved to be a particular problem.
A spokesman for the group said the event "is not about blockading the traffic", but about raising awareness of the increasing levels of pollution. "The blockade is planned to highlight the dangers from smog and to ask drivers to think again about bringing their cars into London."
He said the group hoped that those caught in the ensuing jams will understand the reasons for blocking the traffic.
"It may frustrate them in the short term, but in the long term the public has shown its approval of actions designed to improve the environment and clean-up urban spaces."
The group wants to see an increase in the numbers of people walking and cycling and their shift away from the private car and into cheap, or free public transport.
Reclaim the Streets has mounted several major actions in London in recent months. Camden High Street and Upper Street in Islington, both north London, have been blocked and turned into giant open air street parties in protest against what they claim to be the tyranny of the motor vehicle.
Today's action is part of an expanding campaign in the run-up to next year's centenary of the motor car. Another protest is to be held in Birmingham tomorrow.Reuse content