The Montreal Protocol on Substances that Deplete the Ozone Layer was updated in March 2000. It includes the cumulative amendments to various articles of Vienna Convention for the Protection of the Ozone Layer (adopted on 22 March 1985 ) and the adjustments in levels of production and consumption of the controlled substances as decided by the Parties on the basis of assessment. The adjustments to the Protocol entered into force automatically six months after the date of official notification by the Depositary.

Under Montreal Protocol, they declared their obligation to take appropriate measures to protect human health and the environment against adverse effects resulting or likely to result from human activities which modify or are likely to modify the ozone layer. They d etermined to protect the ozone layer by taking precautionary measures to control equitably total global emissions of substances that deplete it, with the ultimate objective of their elimination on the basis of developments in scientific knowledge, taking into account technical and economic considerations and bearing in mind the developmental needs of developing countries.