The Government's draft plans to tackle illegal air pollution will be published within the next week after ministers decided not to appeal against the High Court's rejection of a bid to delay them until after the election.
Prime Minister Theresa May's official spokesman said the plans would be published between Thursday's local government elections and the deadline of May 9 imposed by a judge last week.
Environmentalists last week won a legal challenge against the Department for Environment, Food and Rural Affairs, which argued that a delay was necessary in order to comply with "purdah" rules restricting government announcements during the election period.
Judge Mr Justice Garnham ruled on April 27 that the draft plan must be published by May 9, with the date for the final plan unchanged on July 31.
Mrs May's spokesman told a regular Westminster media briefing: "We have looked at the judgment from last week and we will not be appealing.
"The court deadline was May 9 and we will be meeting that deadline.
"We will publish at the earliest opportunity after local election purdah is over and before the deadline."
The Government was initially given until April 24 to set out draft measures on reducing illegal levels of nitrogen dioxide pollution after a court ruling last year that existing plans to meet EU-mandated air quality limits were inadequate and must be improved.
But days before the deadline, Defra applied to postpone publication of the draft clean air plan until after the June 8 general election.
Environment Secretary Andrea Leadsom told MPs it was "not appropriate" to publish before the election and pledged to unveil the draft proposals on June 30.
But lawyers for campaign group ClientEarth said there were not sufficient grounds to justify the proposed delay, which could cost lives by allowing excessive pollution to continue for longer.
The judge ruled that purdah was in no sense binding on the courts and was not a "trump card" to be deployed at will by a litigant.
There were 64 deaths each day of the year in the UK and that alone constituted circumstances which were "wholly exceptional" and made immediate publication of the plan essential.
Limits for nitrogen dioxide (NO2) were introduced by EU law in 1999, and were to be achieved by 2010.
Air pollution is linked to an estimated 40,000 early deaths a year in the UK, and some 37 out of 43 regions of the country are in breach of legal limits for nitrogen dioxide.