US environmental regulators can enforce air quality rules even if states sue to block them

The US environmental regulators confirmed they can enforce air quality rules in some states, even if other states successfully challenge the rules in court. This means that states cannot easily avoid their obligations to reduce air pollution by relying on lawsuits from other states.

For years, states have used legal challenges to delay or avoid federal environmental regulations. This ruling means that a single state's lawsuit against air quality rules will not automatically stop enforcement in other states. It makes it harder for polluters to use legal tactics to avoid cleaning up their emissions.