California upholds auto emissions standards in challenge to Trump

California’s clean-air agency voted to push ahead with stricter emissions standards for cars and trucks, setting up a potential legal battle with the Trump administration over the state’s plan to reduce planet-warming gases.

The vote, by the California Air Resources Board, is the boldest indication yet of California’s plan to stand up to President Trump’s agenda. Leading politicians in the state, from the governor down to many mayors, have promised to lead the resistance to Trump’s policies. Trump, backing industry over environmental concerns, said easing emissions rules would help stimulate auto manufacturing. He vowed last week to loosen the regulations. Automakers are aggressively pursuing those changes after years of supporting stricter standards.

But California can write its own standards because of a longstanding waiver granted under the Clean Air Act, giving the state — the country’s biggest auto market — major sway over the auto industry. Twelve other states, including New York and Pennsylvania, as well as Washington, DC, follow California’s standards, a coalition that covers more than 130 million residents and more than a third of the vehicle market in the United States.