Not wanting to provoke another attack from environmentalists, the Bush administration said yesterday that it would delay announcing its plan for overhauling regulation of aging power plants and instead include the plan as part of a more comprehensive package of clean-air policy options in September. President Bush had ordered the U.S. EPA to reassess the “new source review” program by this Friday. The program requires the installation of the latest pollution-control equipment when power plants and refineries are built or significantly upgraded. The U.S. Justice Department under former President Clinton sued dozens of older power plants for failing to improve pollution controls when they modernized their facilities.