Which international agreement was signed to control emissions of ozone-depleting substances?

Correct option is B

The correct answer is (b) Montreal Protocol
Explanation:
· The Montreal Protocol (1987) is a landmark global treaty aimed at phasing out ozone-depleting substances (ODS) such as CFCs, HCFCs, halons, carbon tetrachloride, methyl chloroform, etc.
· It is considered the most successful environmental agreement because all UN member countries have ratified it.
· The protocol works under the Vienna Convention for the Protection of the Ozone Layer (1985).
· It helped reverse damage to the ozone layer, reducing harmful UV radiation that causes skin cancer, cataracts, and ecological imbalance.
· Due to global compliance, the ozone layer is expected to recover by 2050 (UNEP).
Information Booster:
· Signed: 16 September 1987 (Observed as World Ozone Day)
· Implemented: 1989
· Monitored by: UNEP (United Nations Environment Programme)
· Kigali Amendment (2016): Added HFCs (greenhouse gases) to reduce global warming.
· Considered legally binding and includes financial + technological assistance to developing nations.
Additional Knowledge:
(a) Basel Convention – Controls transboundary movement of hazardous waste, not ozone gases. (c) Earth Summit (1992) – Broader environmental meeting; not a specific ozone treaty. (d) Kyoto Protocol (1997) – Targets greenhouse gases, not ozone depletion.