The Trump administration has rejected an Obama-era plan to make automobiles more fuel efficient, putting it and California on a collision course over vehicle emissions.
The Environmental Protection Agency claims standards set to double fuel economy by 2025 were inappropriate.
In a tweet EPA Chief Scott Priutt said the Obama administration's evaluations made assumptions about the standards which were politically charged, too high and didn’t comport with reality.
In 2012, Obama's objectives aimed at cutting oil consumption by about 12 billion barrels over the lifetime of the cars affected and reduced carbon dioxide pollution by about six billion tons.
California, which imposes stricter standards on vehicle emissions than federal rules require, has said it is prepared to sue the EPA if it tries to weaken the standards.