The Montreal Protocol was created so that the mitigation plan could be revised based on periodic scientific and technological evaluations. Following these technical and scientific evaluations, it was carried out in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing) and 1999 (Beijing) in order to accelerate the shortening of the calendar. of the Protocol in question. Again in 2007 (Montreal).