The U.S. Supreme Court yesterday restricted the Environmental Protection Agency’s power to regulate the country’s wetlands.

At issue was the reach of the Clean Water Act and how courts should determine what count as “waters of the United States” under protection of the law, according to a report in The Washington Post.

The ruling affects the EPA’s ability to extend protections to upstream waters in order to protect downstream waters. And it could force the Biden administration to abandon or restart an “effort it began in 2021 to resolve years of uncertainty with new definitions on the type of waterways EPA rules can protect, leaving more of that power up to state governments,” according to the Post.

Environmental advocates asked the court to retain the government’s authority to protect and regulate waterways that affect downstream water quality.

Writing for the majority, Justice Samuel A. Alito said the EPA’s interpretation of its powers went too far. “We hold that the CWA extends to only those wetlands with a continuous surface connection to bodies that are ‘waters of the United States’ in their own right, so that they are ‘indistinguishable’ from those waters.”

Click here for the complete court ruling.