A High Court judge in London has set a date following his ruling earlier this month that the current plan was inadequate and must be improved.
Limits for nitrogen dioxide (N02) were introduced by EU law in 1999, and were to be achieved by 2010.
At a hearing on Monday, Mr Justice Garnham said a new plan to bring air pollution within legal limits must be drawn up by next July.
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He gave the Government until April 24 next year to produce a draft plan, and July 31 to deliver a final one.
On November 2, the judge - ruling on a judicial review action brought by environmental lawyers ClientEarth - declared that the 2015 Air Quality Plan (AQP) was legally flawed.
Campaigners want a national network of clean air zones to be in place by 2018 in cities across the UK.
James Thornton, chief executive of ClientEarth, commented after the hearing: "It is very clear that the Government must now act swiftly and decisively to protect British people from toxic and illegal air pollution.
"Now is the time for the Government to prove that it truly cares about people's health and the environment and take decisive action to tackle illegal air pollution in this country."
A Defra spokeswoman said after the High Court ruling: ''Improving air quality is a priority for this Government and we are determined to cut harmful emissions."
Greenpeace campaigner Areeba Hamid has called for the Government to hold car companies accountable and to put an end to the sale of diesel cars.
Speaking on behalf of the charity, she said: "Defra's over-optimistic estimates of future emissions from diesel cars means the loss of valuable time and resources for several areas in the UK that are suffering an air quality crisis.
"These past years could have been used to force the car companies to stop selling polluting cars and developing cleaner public transport systems, instead of investing billions of NHS resources in treating conditions linked to air pollution,” she added.
However, the RAC says the Government should instead find ways to encourage motorists to switch to cleaner modern vehicles, rather than punishing existing owners.
The organisation’s roads policy spokesman Nick Lyes said: “Demonising diesel vehicles as a whole is also extremely short-sighted. Some of the newest diesel vehicles on the road are also some of the cleanest, and diesels will also play a role in helping to reduce CO2 emissions, which contribute to man-made climate change.”