Video report by ITV News Consumer Editor Chris Choi
A bid by the Government to delay publishing its plans to tackle illegal air pollution until after the General Election has failed at the High Court.
Mr Justice Garnham said a draft plan must be published on May 9 with the July date for publication of the final plan unchanged.
Government lawyers said that publication would drop a "controversial bomb" into the mix of local and national elections.
Ministers were given until 4pm on Monday April 24 to set out draft measures on reducing illegal levels of nitrogen dioxide pollution.
It followed the judge's ruling last year that existing plans to meet EU-mandated air quality limits were inadequate and had be improved.
But days before the deadline, the Department for Environment, Food and Rural Affairs (Defra) applied to postpone publication of the draft clean air plan.
Air pollution causes 40,000 unexplained deaths in the UK each year and associated health complications costs the NHS £20bn per year.
There has been speculation the government's clean air plan could include potentially controversial measure such as charges for motorists to drive diesel vehicles, which cause much of the pollution, in towns and cities.
Defra has argued a delay is necessary in order to comply with election "purdah" rules on government announcements during the election period.
A Downing Street spokeswoman said: "We will consider the judgment and decide what we do next."