Question

when did monteral protocol became effective?

Answer 1

Montreal Protocol, formally Montreal Protocol on Substances That Deplete the Ozone Layer, international treaty, adopted in Montreal on Sept. 16, 1987, that aimed to regulate the production and use of chemicals that contribute to the depletion of Earth's ozone layer.

Answer 2

Montreal Protocol, formally Montreal Protocol on Substances That Deplete the Ozone Layer, international treaty, adopted in Montreal on Sept. 16, 1987, that aimed to regulate the production and use of chemicals that contribute to the depletion of Earth's ozone layer.
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