The British government is seeking to delay publication of a report on tackling air pollution until 15 September, breaking a court deadline for it to comply with European Union legislation.
Concern over air quality has grown since the Volkswagen emissions scandal in September 2015 and reports that real-world emissions exceed those recorded during laboratory tests have put pollution high on the political agenda.
The British government has until 4pm today to come up with a plan to improve air quality and meet nitrogen dioxide limits set by the EU after London's High Court ruled a calculation of future vehicle emissions was too optimistic.
But following British Prime Minister Theresa May's decision to call an early election for 8 June, the government has asked the court for permission for an extension.
"In light of the general election, on Friday [April] 21 we sought an application to consult on the draft air quality plan after the general election and to publish the final plans by 15 September," Mrs May's spokesman said.
Earlier this month, the Financial Times reported that Mrs May had asked officials to develop plans for a scrappage scheme for diesel cars as part of proposals to improve air quality.
Major cities such as Paris, Stuttgart, Athens, Brussels and Madrid are proposing bans, fines and restrictions particularly on diesel cars and London will introduce a levy on the most polluting vehicles entering the city centre from October.
London Mayor Sadiq Khan, a member of the main opposition Labour Party, accused the government of "dithering and delaying".
"In the meantime, every day delayed means another young child will grow up having under-developed lungs and another adult will be dying prematurely," he told Sky News.
"Low income families, small businesses, charities were encouraged to buy diesel vehicles over the last few years. They should be given assistance through a national diesel scrappage fund to help them move from diesel."