The EPA finalized a rule Wednesday that would replace the Obama administration’s signature carbon emissions plan and give states more flexibility in emissions reduction, even as environmental advocates worry about the potential for increased pollution and threaten to sue.

The Affordable Clean Energy rule is the Trump EPA’s answer to the 2015 Clean Power Plan, which for the first time set nationwide limits on greenhouse gas emissions from existing power plants across the country.

The new rule combines a repeal of the Clean Power Plan with new, less stringent emissions reductions guidelines for states and power plants. The Clean Power Plan itself never went effect after 27 states and industry advocates filed a lawsuit, resulting in a stay by the Supreme Court. The case has remained in abeyance as the EPA wrote the ACE rule.

The Clean Power Plan was too “federal-heavy”, and the new rule will rebalance the role of states and the federal government in emissions reduction, EPA Assistant Administrator for Air and Radiation Bill Wehrum said during the announcement of the rule at the agency’s headquarters.

States were required under the Clean Power Plan to devise strategies to start cutting emissions by 2022 from power plants and other high carbon-emitting energy sources, with a target of reducing carbon output by 32 percent below 2005 levels.