The cap and trade program created by the Clean Air Act is a method to limit air pollution in a(n) efficient manner by allowing the market to set the price for meeting government regulation standards. Under the cap and trade program, a limit is set on for a particular area. Pollution in each area are given a(n) for the amount of pollutants they may produce. Facilities that do not use their full allowance may either sell their unused allowance or it. On the other hand, facilities producing a high level of air pollutants are free to either purchase additional allowances or emissions, and therefore can choose whichever is .