President Obama abandoned a contentious new air pollution rule on Friday, buoying business interests that had lobbied heavily against it, angering environmentalists who called the move a betrayal and unnerving his own top environmental regulators.

The president rejected a proposed rule from the Environmental Protection Agency that would have significantly reduced emissions of smog-causing chemicals, saying that it would impose too severe a burden on industry and local governments at a time of economic distress.

Business groups and Republicans in Congress had complained that meeting the new standard, which governs emissions of so-called ground-level ozone, would cost billions of dollars and hundreds of thousands of jobs.