Some states argued their case before the Supreme Court on Feb. 21, 2024, regarding the Environmental Protection Agency's (EPA's) “Good Neighbor Plan,” which requires power plants and other polluting industries located in upwind states like Ohio and Indiana to reduce emissions that create ground-level ozone, commonly known as smog, that flows to downwind states. The states called for the court to issue an “emergency stay” to the plan, a request the justices seemed reluctant to grant.
The Good Neighbor Plan secures significant reductions in ozone-forming emissions of nitrogen oxides (NOX) from power plants and industrial facilities in upwind states, said the EPA, which added that upwind states reducing industrial NOX will result in a reduction of their contributions to smog levels in downwind states.