All I said is its going to end up in courts for sure.
https://www.latimes.com/environment/story/2021-04-26/epa-california-emissions-waiver-reversing-trump
The Environmental Protection Agency announced that it is
reviewing a major Trump-era action that blocked California’s legal authority to set tailpipe emission standards for cars and SUVs that are tougher than federal regulations. After seeking the public’s input, as required by law, the agency intends to rescind the Trump administration’s decision, a spokesman for the agency said.
From that inline linked article
California’s special authority to go further than the federal government in regulating auto pollution dates back to the 1960s, when Los Angeles was enveloped in a thick layer of smog that state officials came to see as a public health crisis. By the time the 1970 federal Clean Air Act took effect, the state had already enacted its own tailpipe emission controls.
Concerned that each state would pass different regulations, Congress decided that the EPA would set vehicle pollution standards for the nation. But it carved out an exception for California, saying that the EPA would be required to grant the state a waiver to set its own rules, provided they were at least as stringent as the federal ones. Other states could choose to follow either California’s regulations or those set by the EPA.
I'm not a constitutional scholar, but I don't believe CA has the right to regulate interstate commerce by banning gasoline vehicles. This equates to another virute signal like banning straws.
https://en.wikipedia.org/wiki/Commerce_Clause