ClientEarth supporters and the Green Party's Caroline Russell outside court last year. Photograph: ClientEarth

ClientEarth supporters and the Green Party’s Caroline Russell outside court last year. Photograph: ClientEarth

Hackney law firm ClientEarth has won another legal battle with the government after the High Court yesterday rejected a bid by ministers to postpone publication of their air pollution strategy.

A previous court ruling in November gave Whitehall until Monday to lay out plans to combat illegal levels of nitrogen dioxide (NO2).

Last week, the government applied to delay the publication until after June’s general election, arguing that it would break “purdah” rules.

This convention is designed to prevent undue influence of an election by restricting government announcements.

But the High Court ruled yesterday afternoon that ministers must publish the draft air pollution plan on 9 May, after local elections.

Mr Justice Garnham also ordered the government to set out its final proposals by 31 July.

ClientEarth’s CEO James Thornton said: “We are delighted with the ruling. We cannot afford more dither and delay from the government. Rather than appeal this decision, they need to get on and produce their plans to bring down air pollution as soon as possible.

“The judge agreed with us that this is a matter of public health, not politics.”

The court accepted that “purdah” rules would affect local elections, a point to which ClientEarth acquiesced.