June 30 was the administration's self-imposed deadline for revealilng proposed changes in the Clean Air Act. The reauthorization of the act brings the first major test of an established environmental program in the new era of cost and regulation cutting. The administration's proposals will challenge the president's assertion that the federal regulatory role can be drastically reduced without jeopardizing basic health and environmental protections.

One set of possible clues to administration thinking on the subject was provided by a leaked draft of the changes made public last week by Rep. Henry Waxman. The White House dismissed the document as the work of low-level bureaucrats; so whether it represented a trial balloon, one among many pending options or the principal working draft is unclear.

We hope it does not represent administration thinking, since the changes in this leaked draft would, among other things, not only shift primary responsibility for clean air to the states, but also remove the Environmental Protection Agency's ability to take over if a state does not act. The document includes a long list of specific exemptions and relaxations from current standards, extensions of compliance deadlines and very broad authority for both state and federal agencies to grant future exemptions. And penalties for those who violate emission standards and federal sanctions for states that do not adopt clean air plans are dropped.

The Clean Air Act is the oldest and most thoroughly studied of the nation's environmental laws. It has achieved a great deal of value. Concentrations of many major pollutants have dropped dramatically, and the number of days of unhealthful air in urban areas is down. But some known pollutants are still uncontrolled, and new unregulated types are emerging.

That the law has shortcomings that need to be corrected has also become evident, and ther are a number of improvements that should be made to reduce red tape, ease federal-state frictions and cut costly and unnecessary delays. Certain of the act's provisions have contributed more to paper work than they have to improving the air. But the needed changes are in the nature of improvements to a basically sound and still much-needed program.