Why in news?  World Ozone Day is observed annually on September 16.

Highlights:

About Vienna Convention for the Protection of the Ozone Layer

• It is a multilateral environmental non-legally binding agreement signed in 1985
• It aims international reductions in the production of chlorofluorocarbons due to their contribution to the destruction of the ozone layer, resulting in an increased threat of skin cancer
• Provided the framework necessary to create regulatory measures in the form of the Montreal Protocol.

About Montreal Protocol

• It is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances responsible for ozone depletion
• Protocol has undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali)
• Ozone depleting substances controlled by the Montreal Protocol contain either chlorine or bromine

Kigali Amendment

• The Kigali Amendment to the Montreal Protocol is legally binding and came into force from 1 January 2019.
• The amendment aims to phase out Hydrofluorocarbons (HFCs), a family of potent greenhouse gases by the late 2040s.