California and 16 other states have sued the Trump administration for loosening vehicle emissions standards.

“We’re not looking to pick a fight with the Trump Administration, but when the stakes are this high for our families’ health and our economic prosperity, we have a responsibility to do what is necessary to defend them”, California Attorney General Xavier Becerra said in a statement.

The legal dispute flows from EPA administrator Scott Pruitt’s move to unravel vehicle efficiency standards for 2022 through 2025 set under Barack Obama. In an April announcement, Mr Pruitt - a climate change skeptic and energy industry ally - said the standards were “too high” and reflected “politically charged expediency”.

For decades, California has had the authority to set its own air quality standards - and, given its size, those rules influence the rest of the nation. Mr Pruitt took direct aim at that role, saying one state should not be allowed to “dictate standards for the rest of the country”.

California’s leadership blasted the decision vowed to fight back. Governor Jerry Brown, who has has championed a push to make California a national leader in reducing emissions and combatting climate change, assailed the White House in announcing the lawsuit.

“They want people to buy more gas, create more pollution”, he said of the Trump administration, denouncing the EPA head as “outlaw Pruitt” and saying he was “riding roughshod over the laws of this country and the health of our people”.

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The Environmental Protection Agency declined to comment.

By challenging the Trump administration in court and asserting state autonomy in setting policy, California added another skirmish to a multifront battle.

Led by Mr Becerra, the state has sued the Trump administration over a range of policies touching on law enforcement, immigration and the environment.

Returning fire, the Trump administration sued California over a trio of laws, enacted since Mr Trump took office, that seek to limit cooperation between local law enforcement and immigration authorities.

California Governor Jerry Brown: 'we know the Trump administration is full of liars'