The Environmental Protection Agency has proposed scrapping the only major rule limiting greenhouse gas emissions from power plants, leaving the United States without a clear national strategy to combat climate change.

On Tuesday, EPA Administrator Scott Pruitt issued a notice of proposed rulemaking for a formal repeal of the Clean Power Plan , the sweeping set of regulations the Obama administration put in place in 2015 to reduce planet-warming gases from the utility sector.

Coal-fired power plants produce about one-third of the countrys electricity and one-third of its greenhouse gases. The plan was the most comprehensive action the U.S. had taken to combat planet-warming emissions, and was meant to spur a faster conversion to sources of energy with fewer emissions.

The Obama administration pushed the bounds of their authority so far with the CPP that the Supreme Court issued a historic stay of the rule, preventing its devastating effects to be imposed on the American people while the rule is being challenged in court, Pruitt said in a news release Tuesday. We are committed to righting the wrongs of the Obama administration by cleaning the regulatory slate.

The repeal would fulfill President Donald Trump s promise to undo former President Barack Obama s environmental legacy. Trump signed an executive order in March instructing Pruitt to review power plant regulations he called stupid and a crushing attack on American industry.

In June, Trump announced the U.S. was withdrawing from the Paris agreement, the global pact to slash emissions that every country other than war-torn Syria has now adopted.

Eliminating the Clean Power Plan makes the country far less likely to meet the goals agreed to under the accord, although a number of states, cities and large corporations have said they will continue to reduce emissions and convert to renewable energy.

The policy, temporarily blocked by the Supreme Court in February 2016, never went into effect, and kiboshing it could save the U.S. $33 billion in avoided costs by 2030, according to the EPAs calculations. (Environmental advocates accused the EPA of cooking the books on its numbers on Tuesday.) But that comes at the cost of public health, according to doctors, who warned on an American Lung Association conference call Tuesday that the Clean Power Plans demise would worsen air pollution and exacerbate illnesses such as asthma.

If implemented, the Clean Power Plan would have provided rewards for early investments in wind and solar power and supplied incentives for energy efficiency programs in low-income communities. Repealing it would make the country more reliant on fossil fuels and delay the sort of energy shift already aggressively underway in places such as Europe and China.

Pruitt said on Monday that hed like to do away with tax credits and other incentives for renewable energy, forcing the nascent wind and solar industries to compete head-to-head with heavily subsidized fossil fuels without government assistance. The war on coal is over, he said at an event with coal miners in Kentucky.