The EPA regulation under the Clean Air Act of 1990 led to sharp reductions in ozone and carbon monoxide levels in major US cities. Stricter fuel standards and requirements for vehicles and power plants to use cleaner technologies cut air pollution by over 60% based on EPA estimates. While the regulation imposed short-term costs estimated at $50 billion, the annual health and other benefits were projected to exceed $100 billion. To ease the transition for industry, the document recommends government support and subsidies for companies implementing the EPA rules.