Add one to the win column for the environment.

Last week, a federal appeals court in Washington, D.C., overturned a regulation issued by the Bush administration that would have given power plants, refineries and factories a way out of installing new air pollution controls.

The ruling, which was in favor of a coalition of states, including New York and California, and a large group of environmental groups, struck down the administration's interpretation of the Clean Air Act.

It said the Environmental Protection Agency went too far in 2003 by creating a rule that critics argued would exempt most equipment changes -- even those that would cause higher emissions --from environmental reviews.

The industry complains that putting in more up-to-date pollution controls would be costly, but we should really be asking what the cost is to the environment. There's no way to misinterpret the underlying purpose of the Clean Air Act: It was designed to protect the environment, and industry and environmental groups alike need to strive for that purpose.

More modern technology and equipment should obviously require more modern and stricter pollution controls. At the very least, states should be able to adhere to the federal regulations that are in place. If states want to be even more protective of the environment -- or challenge federal provisions that they think are not protective enough, such as the "new source review" at issue in last week's decision -- that is their prerogative.

This ruling is one of the most important gains for the environment in the years since the Clean Air Act has been enacted and repeatedly challenged in the courts.

The appellate court should be lauded for its recognition of the importance of updating controls and maintaining standards to keep the nation's air free of pollution.