In the United States, the acid rain related emission trading system was principally conceived by C. Boyden Gray, a G.H.W. Bush administration attorney. Gray worked with the Environmental Defense Fund (EDF), who worked with the EPA to write the bill that became law as part of the Clean Air Act of 1990. The new emissions cap on NOx and gases took effect in 1995, and according to "Smithsonian" magazine, those acid rain emissions dropped 3 million tons that year. In 1997, the CoP agreed, in what has been described as a watershed in international environmental treaty making, the Kyoto Protocol where 38 developed countries (Annex 1 countries) committed themselves to targets and timetables for the reduction of GHGs. These targets for developed countries are often referred to as Assigned Amounts.