The U.S. Supreme Court will decide whether to block key parts of the Obama administration's plans for environmental regulations.
The court will hear a case that involves the power of the Environmental Protection Agency.
The EPA has the authority to regulate the emissions from mobile sources, like cars. But they have also claimed that authority gives them the power to regulate emissions from stationary objects, like power plants and factories.
Critics say the agency is overreaching and going beyond what the law allows it to do.