Reformulated gasoline (RFG) is a cleaner-burning blend of gasoline that reduces motor fuel emissions. While RFG contains the same ingredients found in conventional gasoline, it reduces some of the more harmful, toxic compounds and adds more combustible, cleaner-burning compounds. As a result, RFG can be efficiently, safely and cost-effectively used in today's cars—using the same refueling methods and with no appreciable difference on vehicle performance. Since its introduction in January 1995, RFG has eliminated approximately 300 million tons of pollution from the nation's atmosphere. (U.S. Environmental Protection Agency)

This definition is in context to Ethanol. See more contextual defintions for Reformulated Gasoline.