The Environmental Protection Agency has repealed major parts of Biden-era carbon dioxide standards for coal- and natural gas-fired power plants while retaining some requirements for new gas and coal facilities. EPA Assistant Administrator Aaron Szabo said new natural gas plants must still meet 2015 standards and 2024 efficiency requirements, while Obama-era rules for new coal plants also remain. A supplemental proposal would find that the Clean Air Act does not authorize EPA to regulate power plants' greenhouse-gas emissions, potentially removing the remaining standards and delaying future federal action. The Biden rule had required existing coal plants and new gas plants to prevent 90% of carbon dioxide emissions from reaching the atmosphere. EPA Administrator Lee Zeldin said the rollback would lower electricity prices and protect reliable energy supply. Environmental and legal groups said they expect to challenge the action.