WASHINGTON (AP) — In a last-minute slap at President Donald Trump, a federal appeals court struck down one of his administration’s most momentous climate rollbacks on Tuesday, saying officials acted illegally in issuing a new rule that eased federal regulation of air pollution from power plants.

The Trump administration rule was based on a “mistaken reading of the Clean Air Act,” the U.S. Court of Appeals for the District of Columbia ruled, adding that the Environmental Protection Agency “fundamentally has misconceived the law.” The decision is likely to give the incoming Biden administration a freer hand to regulate emissions from power plants, one of the major sources of climate-damaging fossil fuel emissions.

EPA spokeswoman Molly Block called the agency’s handling of the rule change “well-supported.” The court decision “risks injecting more uncertainty at a time when the nation needs regulatory stability,” she said.

Environmental groups celebrated the ruling by a three-member panel of the Court of Appeals.

“Today’s decision is the perfect Inauguration Day present for America,” said Ben Levitan, a lawyer for the Environmental Defense Fund, one of the groups that had challenged the Trump rule in court.

The ruling “confirms that the Trump administration’s dubious attempt to get rid of common-sense limits on climate pollution from power plants was illegal,” Levitan said. “Now we can turn to the critically important work of protecting Americans from climate change and creating new clean energy jobs.”

A coalition of environmental groups, some state governments and others had challenged the Trump administration’s so-called Affordable Clean Energy, or ACE, rule for the power sector. The rule, which was made final in 2019, replaced the Clean Power Plan, the Obama administration’s signature program to address climate change.