MPSC 2026 Prelims Paper-I · Question 31 of 100

Correct — option (1), 'Only (a)'. The Montreal Protocol on Substances that Deplete the Ozone Layer, adopted on 16 September 1987 and in force from 1 January 1989, is a control treaty with one object: to phase out the production and consumption of substances that destroy stratospheric ozone. Statement (a) is a near-exact statement of that object — reduction of the production and consumption of ozone-depleting chlorofluorocarbons in order to check depletion of the ozone layer — and it is the operative language of the treaty, which sets out control schedules substance by substance, with baseline years and phase-out dates, for CFCs first and then for halons, carbon tetrachloride, methyl chloroform, methyl bromide and the transitional HCFCs. Statement (a) therefore stands. Statement (b) describes a general programme for the protection of the earth and its environment, ecological balance and biodiversity. That is a fair description of the broad environmental agenda expressed through the Stockholm Declaration of 1972 and, for biodiversity specifically, through the Convention on Biological Diversity of 1992; it is not what the Montreal Protocol does. The Protocol is deliberately narrow — it names chemicals and fixes dates — and its success is generally attributed to precisely that narrowness. Statement (b) is therefore not related to it. Statement (c), the study of pollution at the pole, describes a research activity. The discovery of the Antarctic ozone hole, reported in 1985 by Farman, Gardiner and Shanklin of the British Antarctic Survey, is what gave the negotiations their urgency, and the Protocol's assessment panels review the science of ozone depletion including the polar hole; but the treaty itself does not establish or conduct polar pollution research, and a statement describing a study programme does not describe this instrument. Only statement (a) survives, so option (1) is correct.

• (2)Only (b) — Selects the vague, all-purpose environmental statement and rejects the one that names the Protocol's actual subject matter. Statement (b) would fit the Stockholm Declaration of 1972 or the Convention on Biological Diversity of 1992 far better than it fits an instrument whose text consists of control schedules for named chemicals. A candidate lands here by assuming that the broadest-sounding statement must be the treaty's purpose, when in fact the Montreal Protocol is the standout example of an environmental agreement that worked because it refused to be broad.
• (3)(a) and (c) — Right about statement (a) and wrong to add statement (c). The association is understandable — the Antarctic ozone hole reported in 1985 is what drove governments to the negotiating table two years later — but a cause of a treaty is not a provision of it. The Protocol regulates the manufacture, trade and consumption of ozone-depleting substances; polar atmospheric research is carried out by national scientific programmes under the Antarctic Treaty system and by bodies such as the World Meteorological Organization, not by this instrument.
• (4)All of the above — Requires all three statements to describe the Montreal Protocol, and two of them do not. An inclusive option like this one — offered eleven times in this booklet — is defensible only when every named item can be independently shown to belong, and it collapses the moment one item fails. Here two fail: the generic biodiversity and ecological-balance language of statement (b) belongs to other instruments, and the polar research of statement (c) is an activity the Protocol neither establishes nor performs.

Stratospheric ozone, concentrated roughly 15 to 35 km above the surface, absorbs most of the Sun's ultraviolet-B radiation and is the reason terrestrial life is possible at all. Chlorofluorocarbons — stable, non-toxic, non-flammable compounds used as refrigerants, aerosol propellants, solvents and foam-blowing agents — are so unreactive that they survive to reach the stratosphere intact. There ultraviolet light breaks them apart and releases chlorine atoms, each of which catalyses the destruction of many ozone molecules before it is removed, which is why very small quantities of a gas can have a very large effect. The mechanism was proposed by Mario Molina and F. Sherwood Rowland in 1974, and the observational proof came in 1985 with the report of a deep seasonal thinning of ozone over Antarctica. The international response is a two-tier structure that is worth learning as a model: the Vienna Convention of 1985 established the framework and the obligation to cooperate, and the Montreal Protocol of 1987 supplied the binding, dated, substance-by-substance control schedules. Framework convention first, protocol with hard commitments afterwards, is the same architecture later used for climate with the UNFCCC and the Kyoto Protocol.

The Montreal Protocol is habitually described as the most successful environmental treaty ever concluded, and the reasons are examinable in themselves. Its obligations were specific and measurable; substitutes for the controlled chemicals existed or could be developed; the number of producing firms was small enough to make compliance verifiable; developing countries were given a grace period as Article 5 parties and a Multilateral Fund, established in 1991, to meet the incremental costs of conversion; and the treaty was designed to be tightened as science improved, which it was, through the London, Copenhagen, Montreal and Beijing amendments. Its most recent extension, the Kigali Amendment of 2016 in force from 1 January 2019, moves beyond ozone altogether: it phases down hydrofluorocarbons, which do not deplete ozone but are extremely potent greenhouse gases and came into wide use precisely as CFC substitutes. India ratified the Kigali Amendment in 2021. The date of adoption, 16 September, is observed as World Ozone Day.

• Vienna Convention for the Protection of the Ozone Layer, 1985 — the framework agreement that created the obligation to cooperate on research and monitoring. The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted under it on 16 September 1987 and entered into force on 1 January 1989.
• The Protocol controls production and consumption of named ozone-depleting substances on dated schedules: CFCs and halons first, then carbon tetrachloride, methyl chloroform, methyl bromide and the transitional HCFCs. It works by naming chemicals and fixing deadlines, not by stating general environmental aims.
• The Antarctic ozone hole was reported in 1985 by Farman, Gardiner and Shanklin of the British Antarctic Survey; the underlying chemistry of chlorine-catalysed ozone destruction had been proposed by Mario Molina and F. Sherwood Rowland in 1974, work for which they later shared the Nobel Prize in Chemistry with Paul Crutzen.
• The Multilateral Fund, established in 1991, meets the incremental costs of compliance for developing countries, which are given a grace period as Article 5 parties. This combination of differentiated deadlines with financial support is the feature most often credited for the treaty's near-universal participation.
• The Kigali Amendment of 2016, in force from 1 January 2019, extends the Protocol to the phase-down of hydrofluorocarbons — chemicals that do not deplete ozone but are powerful greenhouse gases, and which spread as substitutes for CFCs. India ratified it in 2021. 16 September is observed as World Ozone Day.

• Confusing the cause of a treaty with its content. The Antarctic ozone hole prompted the Montreal Protocol, but the Protocol regulates chemicals; a statement describing polar research describes the science that motivated it, not the instrument itself.
• Accepting a broad, pleasant-sounding environmental statement as the aim of a specific treaty. Language about ecological balance and biodiversity fits the Stockholm Declaration or the Convention on Biological Diversity, and one of the reasons the Montreal Protocol succeeded is that it never used it.
• Mixing up ozone depletion with global warming. They are different problems with different chemicals and different treaties, and the Kigali Amendment is the single place where they meet — HFCs are climate pollutants regulated under an ozone treaty because they arrived as ozone-friendly substitutes.

International environmental agreements are asked in four regular shapes: convention-to-subject matching, the year and place of adoption, the substances or species controlled, and the protocol-to-parent-convention relationship. MPSC favours the first two and the statement-verification format used here, in which one accurate statement of a treaty's object is set against generic environmental language that would fit almost any instrument. The defence is to hold, for each agreement, a single sentence naming what it actually regulates — chemicals, waste, species, wetlands or emissions — because generic statements can then be rejected on sight. Note also the shape of this option set: three named options and one inclusive option. An inclusive option is right only when every listed item survives inspection, so it should be tested item by item like any other.

No directly related past PYQ was found.

• practice — not a real PYQ

  The Montreal Protocol, 1987 was adopted under which framework convention ?

  • (a)Vienna Convention for the Protection of the Ozone Layer, 1985
  • (b)United Nations Framework Convention on Climate Change, 1992
  • (c)Basel Convention on hazardous wastes, 1989
  • (d)Stockholm Convention on persistent organic pollutants, 2001

  Answer(a) Vienna Convention for the Protection of the Ozone Layer, 1985 — the framework agreement that created the duty to cooperate on ozone research and monitoring, under which the Montreal Protocol two years later supplied the binding, dated phase-out schedules. The same two-tier design was later used for climate, with the UNFCCC as framework and the Kyoto Protocol as the instrument carrying commitments.

• practice — not a real PYQ

  The Kigali Amendment of 2016 to the Montreal Protocol provides for the phase-down of which group of substances ?

  • (a)Chlorofluorocarbons (CFCs)
  • (b)Hydrochlorofluorocarbons (HCFCs)
  • (c)Hydrofluorocarbons (HFCs)
  • (d)Methyl bromide

  Answer(c) Hydrofluorocarbons — chemicals that do not deplete stratospheric ozone at all but are extremely potent greenhouse gases, and which came into wide use precisely because they were acceptable substitutes for CFCs. The Kigali Amendment entered into force on 1 January 2019 and India ratified it in 2021; CFCs, HCFCs and methyl bromide were already covered by the Protocol's earlier schedules.