The Environmental Protection Agency will start the process of repealing the old administration's ambitious climate policy on Tuesday. That’s according to Scott Pruitt, head of the EPA, who announced the news during a speech in Kentucky today, reports the New York Times. “The war on coal is over,” he said. “Tomorrow in Washington D.C., I will be signing a proposed rule to roll back the Clean Power Plan.”

Obama’s Clean Power Plan laid out rules that demanded power plants reduce their carbon emissions by 32 percent in time for 2030. As we’ve pointed out before, it was a major component of America’s attempt to cut emissions under the Paris climate pact, contributing as much as 12 percent of the total savings that needed to be made. That means the move will make it difficult for the U.S. to meet its commitments to the Paris accord—but then, Donald Trump has already announced that he plans to exit the agreement.

Scrapping the plan won’t come as a surprise to most people: Donald Trump has repeatedly promised to roll back the rule, arguing that it damages the American economy. It won’t, however, be a swift process. The Times points out that the repeal will have to go through a public-comment period, and that the administration may also have to come up with an alternative rule because the EPA is legally required to regulate emissions in some form or another. With plenty of opposition against the repeal expected, that could involve complex legal battles and, potentially, years of back-and-forth.