California cannot bring in tough emissions laws without EPA approval

Two years ago, California passed legislation requiring car-makers to cut vehicle emissions by 30% by 2016.

But for the measure to take effect, the Environmental Protection Agency (EPA) must give its approval.

State governor Arnold Schwarzenegger said there was no legal basis for the EPA to stand in California's way.

An EPA spokeswoman said the agency planned to make a decision on the legislation by the end of December.

If the legal action is successful, 11 other US states have said they will follow California's lead on emissions levels, and five more are considering the move.

'Our future'

California needs the EPA to grant a waiver because the state's legislation seeks to implement stricter standards than those imposed under national law.

Arnold Schwarzenegger believes the environment is a key issue

Speaking at a news conference, Mr Schwarzenegger accused the federal government of "ignoring the will of tens of millions of people" by failing to approve the legislation.

He said: "Our future depends on us taking action on global warming right now.

"There's no legal basis for Washington to stand in our way."

The 16-page lawsuit filed by the state attorney general's office warns that greenhouse gas emissions from vehicles are rising more quickly than from any other source.

"The longer the delay in reducing these emissions, the more costly and harmful will be the impact on California," it said.

US car-makers are fighting California's plans to cut emissions levels in the courts.

Industry groups say the proposed standards would raise the cost of vehicles and could force America's embattled car makers into further difficulties.

In April, the US Supreme Court ruled that the EPA, which had challenged the California law, was wrong to say that it did not have the power to regulate exhaust gases from new cars and trucks.

In a separate move, Mr Schwarzenegger last year signed a bill making California the first US state to impose limits on the state's greenhouse gas emissions, with a target of 25% by 2020.