Even as President Trump struggles to deal with the coronavirus pandemic, he hasn’t forgotten his drive to undo environmental regulations — and undermine more of Barack Obama’s legacy.

His administration is expected to announce a final rule on Tuesday that would roll back fuel efficiency standards for cars and pickup trucks, “virtually undoing the government’s biggest effort to combat climate change,” reports the New York Times.

“The new rule … would allow vehicles on American roads to emit nearly a billion tons more carbon dioxide over the lifetime of the cars than they would have under the Obama standards,” the Times says.

Right now, of course, the pandemic has dramatically reduced traffic on U.S. streets and highways, but eventually it will return to normal and air pollution levels will rapidly rise.

The rule change is likely to be challenged in the courts, but if it is implemented it would roll back a 2012 requirement that automakers’ fleets improve fuel mileage to about 54 mpg over the next five years. Instead, they would have to average only 40 mpg.

Trump is expected to promote the new rule, prepared by the EPA and the Transportation Department, as necessary to prop up the economy during the ongoing pandemic.

The president’s critics — and even some of the world’s largest automakers — have protested the change.

“This is not just an inopportune moment to finalize a major rule-making,” said Sen. Thomas R. Carper (D-DE), the ranking Democrat on the Senate Environment Committee. “In this case, it’s a completely irresponsible one.”

For environmentalists, the auto-emissions rule is the latest and largest step in Trump’s “quest to dismantle the United States’ efforts to fight climate change,” the Times says.

Earlier steps included pulling the U.S. out of the global Paris climate-change accord, weakening rules to curb greenhouse gas emissions from coal plants and undermining or ignoring the science behind environmental regulations.

Trump’s supporters say his moves are aimed primarily at consumers who generally prefer larger, less-fuel-efficient vehicles, such as pickup trucks and SUVs.

“The auto industry wanted a smoother glide path to a more efficient future,” said Dr. Victor of the University of California, San Diego.

Instead what they got was the populist politics of the far right, which is blowing up in their faces.”