London Mayor Boris Johnson may introduce temporary bans on cars and trucks on some of the city's busiest roads during days when air pollution is at its most dangerous level. Johnson would consider special measures such as banning vehicles during 'the very worst pollution episodes in London,' he said in a written response to a question from Darren Johnson, a Green Party member of the city's legislative assembly. The city of 7.5 million residents has the worst record for nitrogen dioxide pollutants among European capitals and one of the worst for airborne particles. Tailpipe emissions are major contributors to both, and conditions can be worsened by weather. 'We now know that both the scale of the problem and the urgency is much greater than previously stated,' Darren Johnson said in an e-mailed statement today that included the mayor's answer. The European Union is considering fining Britain for failing to meet anti-pollution targets, while the British government has asked the EU for more time to meet the guidelines. The mayor would introduce the special measures regardless of whether the time extension is granted, he said. Boris Johnson published a draft air quality policy in October which says the city may declare 'action days' in central London when airborne particle pollution exceeds EU targets. One of the worst particle pollution areas is along Marylebone Road, a major route between central and west London. Banning vehicles 'would have all sorts of impacts on businesses dependent on daily deliveries,' said Gordon Telling, a policy director at the Freight Transport Association. The group is meeting with city officials next week to discuss alternatives such as increased evening deliveries and using more electric vehicles, Telling said. A spokesman for the London Chamber of Commerce said the group was studying the issue. 