The left opposes revoking the waiver, arguing that the move will harm the environment and is unlikely to hold up in court.

“In announcing on Wednesday his determination to revoke California’s longstanding authority to set its own air pollution standards, President Trump finds himself arrayed against the plain language of the Clean Air Act, California’s historical role as a laboratory for tough new environmental rules and the express wishes of several major automakers and two-thirds of the American people.” (Editorial Board, New York Times)

The Trump administration is set to formally revoke California's tailpipe waiver under the Clean Air Act on Wednesday, according to a source with knowledge of the change.

The move is a major strike in the ongoing battle between the Trump administration and California over the state's right to enact more stringent air pollution standards due to its poor air quality.

The Trump administration will announce as early as Wednesday it is revoking California’s authority to set its own greenhouse gas and vehicle fuel efficiency standards and barring all states from setting such rules, two auto industry officials said on Tuesday.

The move is sure to spark legal challenges over issues including states' rights and climate change that administration officials say could ultimately be decided by the U.S. Supreme Court.

President Trump is expected Wednesday to revoke a decades-old rule that empowers California to set tougher car emissions standards than those required by the federal government — putting the state and the administration on a path to years of fighting in court.

The Trump administration plans this week to revoke California’s long-standing right to set stricter air pollution standards for cars and light trucks, the latest step in a broad campaign to undermine Obama-era policies aimed at cutting greenhouse gas emissions to combat climate change, two senior administration officials said.

The move threatens to set in motion a massive legal battle between California and the federal government, plunge automakers into a prolonged period of uncertainty and create turmoil in the nation’s auto market.

The White House, blindsided by a pact between California and four automakers to oppose President Trump’s auto emissions rollbacks, has mounted an effort to prevent any more from joining the other side.

Toyota, Fiat Chrysler and General Motors were all summoned by a senior Trump adviser to a White House meeting last month where he pressed them to stand by the president’s own initiative, according to four people familiar with the talks.