On the Friday just before Christmas, a federal appeals court rejected attempts by the Environmental Protection Agency (EPA) to weaken requirements for attainment of federal ozone standards. http://pacer.cadc.uscourts.gov/docs/common/opinions/200612/04-1200a.pdf 

The court deferred to the EPA's expertise in determining that a new 8-hour standard is more protective of public health than the old 1-hour standard, and allowed the agency to revoke the 1-hour standard. However, the court also determined that the agency could not weaken Congressional mandates for steady, sustained progress toward attainment of federal air quality standards. Specifically, the court ruled that the agency cannot weaken or eliminate:

• new source review requirements;
• penalties for states' failure to meet deadelines for attain the 1-hour standard,
• rate-of-progress milestones; and
• mobile vehicle conformity demonstrations.