In the final proposal, Obama will unveil measures that are tougher than those in the 2014 draft proposal. The rules seek to curb carbon emissions from power plants by 32 percent by 2030.
The court wrapped up on Monday, supporting the use of a controversial drug for executions by lethal injection. The justices also set up cases to be heard next term on affirmative action and abortion.
Monday's decision from the high court technically only applies to the Clean Air Act's standards on mercury emissions from power plants. But it could affect future EPA regulations, legal experts say.
The Environmental Protection Agency hasn't outlined any specific emissions limits for aircraft engines, but it has begun the process that would lead to them.
General Electric is entering the final year of a billion-dollar cleanup of PCB-contaminated water. The project was once controversial — now, even some early critics are asking for it to be continued.
The regulations are intended to clarify recent court decisions on which bodies of water are protected, but many farmers and congressional Republicans oppose what they call an EPA "land grab."
The rules are aimed at limiting the amount of hazardous pollutants coming from coal- and oil-fired utility plants. They're being challenged by industry groups and more than 20 states.