Trump, on the other hand, argues via Twitter that the exemption must be stopped "in order to produce far less expensive cars for the consumer, while at the same time making the cars substantially SAFER".
USA automakers contend that without year-over-year increases in fuel efficiency that align with global market realities their vehicles could be less competitive, potentially resulting in job losses.
Since Trump's 2016 election, California state officials have filed dozens of lawsuits over the administration's actions on a host of issues from immigration and healthcare to the environment.
Newsom, admitting his "deep frustration", cited the support from the auto industry and accused the administration of kowtowing to special interests.
"The ability to have more efficient...vehicles is incredibly important and to take that tool away from the state just makes zero sense and takes us backwards", Walke said. Ford, Honda, BMW and Volkswagen went around the EPA by reaching an agreement with California in July.
"We can not afford to backslide in our battle against climate change", Becerra said.
A day earlier, Gov. Gavin Newsom and mayors of the state's 13 largest cities sent Trump a letter asking his administration to provide more aid to fight homelessness, including an additional 50,000 housing vouchers for the poor.
The Justice Department recently launched an antitrust investigation into a deal between California and four major vehicle manufacturers for tougher pollution and related mileage requirements than Trump's administration sought. A bill by Democratic Assemblyman Phil Ting would mean people could only get that money if they buy a auto from a company that has agreed to follow California's emission standards. "Full stop", he said, noting the opposition of oil companies through the years to the waiver granted to California.
Within weeks, the Trump administration is expected to publish a national federal rule that significantly weakens Obama-era standards for tailpipe emissions of carbon dioxide, the leading greenhouse gas fueling climate change. Because California's auto-emission standards improve air quality, decrease climate pollution, save consumers money and advance fuel-efficient vehicle technology for everyone. That compares with 4.7% yearly reductions through 2025 under the Obama standards. Trump wants the current standard of 37 miles per gallon to continue until 2026 without rising.
After automatically following US auto-emissions rules for many years, the Canadian government signed a memorandum of understanding with California in June committing to co-ordinate with the state on tougher vehicle-emissions requirements, as well as on measures to encourage more consumers to buy electric vehicles. Now the standard is 26 mpg (11 km/L).
Markey and Delaware U.S. Sen.
Trump's action came on the same day teenage climate activist Greta Thunberg was addressing the US Congress and urging legislators to treat climate change "as the existential crisis it is".
The DOT chief did say that "the updated standards will be reasonable", and likely will not be rolled back as much as the administration had first suggested during a news conference late past year.
"I haven't wanted to post the article [about Trump's decision] on social media", said Rajkovacz. An August investigation by nonprofit consumer advocacy organization Consumer Reports, however, contradicts that assertion.
"I wish Trump would have his EPA enforce against actual environmental problems, but I guess that would be too much to ask", wrote Wiener, whose district includes San Francisco.