💡 The 4-Level Response to ODS — From Framework to Rules
Think of the international response to ozone depletion as a 4-storey building. The Vienna Convention (1985) is the foundation — an agreement that the problem exists and cooperation is needed. The Montreal Protocol (1987) is the first floor — the actual binding rules, phase-out schedules, and enforcement. The Kigali Amendment (2016) is the second floor — expanding the building to cover HFCs (the replacement that became a climate problem). India’s ODS Rules (2000) are the interior furnishings — how India implements all these commitments domestically. Each level builds on the one below, and together they represent humanity’s most successful environmental intervention ever.
1
Vienna Convention for the Protection of the Ozone Layer (1985)
The framework treaty — agreed to act, but without binding controls
Vienna Convention — Key Facts
- Adopted: 22 March 1985, Vienna, Austria
- Nature: A framework convention — sets principles and cooperation mechanisms but does NOT mandate any specific ODS phase-out. Often called the “agree to agree” treaty.
- What it does:
- Requires parties to cooperate through research, data sharing, and systematic observation of the ozone layer
- Commits countries to take “appropriate measures” to protect the ozone layer
- Creates the institutional framework for future protocols (like Montreal)
- Significance: First international environmental treaty to be recognised and acted upon before the problem became irreversible — a rare example of preventive environmental diplomacy. Ozone depletion was confirmed by Joe Farman’s data the same year.
- Parties: 116 countries initially; now nearly universal
- 40th Anniversary: 2025 — WMO issued a special Ozone Bulletin for the occasion (World Ozone Day, September 16, 2024 marked the 40th anniversary)
- India: Ratified the Vienna Convention on 18 March 1991
- Secretariat: Ozone Secretariat based at UNEP headquarters, Nairobi, Kenya
🌐 Vienna Convention 1985
Framework · Research · Cooperation
- Framework only — no binding controls
- Commits to research + data sharing
- Principle: cooperate to protect ozone
- “Agree to agree” on future action
- Created the platform for Montreal Protocol
- India ratified: 18 March 1991
📋 Montreal Protocol 1987
Binding Controls · Phase-out Schedules · MLF
- Legally binding controls on specific ODS
- Phase-out schedules with deadlines
- Multilateral Fund for developing countries
- Trade sanctions for non-compliance
- 198 parties — first universally ratified UN treaty
- India joined: 19 June 1992
2
Montreal Protocol (1987) — The World’s Most Successful Environmental Treaty
First universally ratified UN treaty · Phased out 99%+ of ODS · Model for global action
Montreal Protocol — Everything UPSC Needs
- Signed: 16 September 1987 — now celebrated as World Ozone Day annually
- In force: 1 January 1989
- Parties: 198 (197 states + EU) — FIRST AND ONLY treaty in UN history to achieve universal ratification
- Scope: Controls production AND consumption of ~100 ODS listed in Annexes A, B, C, E, F
- Article 5 parties: Developing countries — given longer phase-out timelines and financial support through MLF
- Kofi Annan quote: “Perhaps the single most successful international agreement to date”
- Impact so far: Phased out >99% of controlled ODS globally vs 1990 levels; prevented 443 million skin cancer cases (US alone); ozone layer recovering
- Key mechanisms:
- Phase-out schedules differentiated by country type (developed vs developing)
- Multilateral Fund (MLF) — finances developing country transitions
- Trade controls — bans trade in ODS with non-parties
- Annual data reporting — every party must report ODS production/consumption
- Non-compliance mechanism — MOP (Meeting of Parties) reviews compliance
- Governance: Meeting of Parties (MOP) — annual governance body. Open-ended Working Group (OEWG) for technical work. Combined COP/MOP meetings for Vienna Convention + Montreal Protocol together.
- Latest MOP: COP 13/MOP 36 (2024, Bangkok) — decisions on HFC-23 emissions, energy-efficient cooling, monitoring. Countries negotiated future cooling technology solutions.
The Multilateral Fund (MLF) — The Financial Heart of Montreal Protocol
MLF — Most Important Mechanism for UPSC
- Established: 1991 — under Article 10 of the Montreal Protocol
- Purpose: Finances developing countries (Article 5 parties) to meet their ODS phase-out obligations. Covers: technology transfer, training of technicians, industrial conversion, institutional strengthening.
- Who funds it: Developed countries (non-Article 5 parties) are the donors
- Who benefits: Developing countries (Article 5 parties) are the recipients. India has been a major beneficiary for HCFC phase-out.
- Disbursement: Over US$4 billion disbursed since 1991 — to over 140 developing countries
- Implementing agencies: UNDP, UNEP, UNIDO, World Bank — each assigned specific sectors
- UPSC trap: MLF helps DEVELOPING countries, not developed countries. Developed countries are donors, not recipients.
- Climate-ozone connection: The “polluter pays” principle applies in reverse — developed countries, who used CFCs the most, fund developing countries to avoid the same mistakes
Key Amendments to Montreal Protocol — Evolution Over Time
1990
London Amendment — CFCs and halons accelerated
Agreed to phase out CFCs and halons entirely by 2000 (developed) and 2010 (developing). Added carbon tetrachloride and methyl chloroform to controlled list. Created the Multilateral Fund formally.
1992
Copenhagen Amendment — HCFCs added, faster CFCs
Moved up CFC phase-out to 1996 (developed countries). Added HCFCs to controlled list for the first time (though as transitional substances). Added methyl bromide (agricultural fumigant) to controlled list.
1997
Montreal Amendment — Methyl Bromide controls tightened
Established specific methyl bromide phase-out schedule. Stricter controls on HCFC production. Trade controls strengthened.
1999
Beijing Amendment — HCFC production controls
Added controls on HCFC production (not just consumption). Further tightened trade measures. Added bromochloromethane to controlled list.
2007
Montreal Adjustment — HCFC phase-out accelerated
Accelerated HCFC phase-out schedule: developing countries to freeze by 2013 and completely phase out by 2030 (moved up from 2040). Developed countries to phase out HCFCs by 2020.
2016
Kigali Amendment — HFCs (Climate, not ozone) KEY
Added HFCs (Hydrofluorocarbons) to controlled substances — the first time the Montreal Protocol targets a substance for its climate impact rather than ozone depletion. HFCs don’t deplete ozone but are powerful greenhouse gases. See Section 3 below.
3
Kigali Amendment 2016 — From Ozone to Climate
The amendment that turned an ozone treaty into a climate treaty too — targeting HFCs
Kigali Amendment — Core Facts
- Adopted: October 15, 2016 — at the 28th Meeting of Parties (MOP-28), Kigali, Rwanda (Decision XXVIII/1)
- In force: 1 January 2019
- Parties ratified: 164 parties (as of 2024)
- Target: HFCs (Hydrofluorocarbons) — NOT ozone depleting, but potent greenhouse gases (GWP up to 14,800× CO₂). HFC emissions growing at 8–10% per year globally.
- Goal: Phase down HFC production and consumption by 80–85% over next 30 years
- Climate impact: Expected to prevent up to 0.5°C of global warming by 2100 — one of the largest single climate interventions
- Why Montreal (not UNFCCC)? Piggybacks on Montreal’s proven institutional machinery — universal ratification, compliance mechanisms, MLF financing, annual MOP reviews. UNFCCC/Kyoto had failed to achieve similar results.
- India ratified: September 2021 (Cabinet approved; PIB notification)
- India’s domestic commitment under Kigali: Amend ODS Rules to bring HFCs under regulatory control (mid-2024 target)
Three-Track Phase-Down Schedule — Different Countries, Different Timelines
Developed Countries
Non-Article 5 · USA, EU, Japan
Baseline: Average 2011–2013 HFC + 15% of HCFC baseline. First reductions from 2019. Phase-down to 15% of baseline by 2036. 85% cut by 2036.
Developing Countries — Group 1
China, Brazil, South Africa + most developing
Baseline: Average 2020–2022 + 65% HCFC baseline. Freeze by 2024. 10% cut 2029. 85% cut by 2045.
Developing Countries — Group 2 🇮🇳
India, Pakistan, Iran, Iraq, Gulf states
Baseline: Average 2024–2026 + 65% HCFC baseline. Freeze by 2028 (or 2030 if cooling demand exceeds threshold). Phase-down: 10% (2032) → 20% (2037) → 30% (2042) → 85% (2047).
🔴 India’s Kigali Position — Why India Got Special Treatment UPSC Important
- India’s negotiating logic: India argued it needed later baselines and freeze years because its cooling sector is still in rapid growth — more ACs and refrigerators are being installed each year than anywhere else. India needs “room to grow” in HFC use before cutting.
- India’s HFC freeze year: 2028 (with possible deferral to 2030 if cooling sector growth exceeds agreed threshold following 2024-25 technology review)
- Group 2 advantage: By using 2024–2026 as baseline (instead of 2020-22 like China), India’s baseline will be higher — giving it more headroom for cuts while still expanding cooling access
- HFC-23 commitment: India committed to eliminate HFC-23 (a potent GHG by-product of HCFC-22 manufacturing, GWP = 14,800× CO₂) — orders issued Oct 2016 to HCFC-22 manufacturers to incinerate HFC-23 rather than venting it
- India’s cooling challenge: HFC consumption for space cooling projected to increase ~9 times — from ~28,000 MT (2025) to ~2,40,000 MT (2050) — the fastest growth trajectory of any country (NRDI India December 2025 report)
4
HFO Alternatives to HFCs — The Next-Generation Refrigerants
The refrigerant evolution: from ozone killers to climate bombs to the uncertain next step
💡 The Refrigerant Relay Race — Each “Baton” Creates a New Problem
The history of refrigerants is a relay race where each handoff solves the previous runner’s problem but creates a new one for the next. CFCs were brilliant — stable, non-toxic, efficient — until we discovered they destroy ozone. HCFCs replaced them — less ODP — until we discovered they too deplete ozone and warm the climate. HFCs replaced them — zero ODP — until we discovered their GWP is 14,800× CO₂. Now HFOs promise to fix the climate problem — but they degrade into PFAS (“forever chemicals”) that pollute water. The final handoff? Natural refrigerants — ammonia, CO₂, propane — used for over a century, now being reconsidered as the sustainable endpoint.
The Refrigerant Evolution — From CFCs to Natural Refrigerants
❌ CFCs
ODP: High
GWP: Very High
Problem: Destroy ozone layer
Phase-out: 1996/2010
→
⚠️ HCFCs
ODP: Lower (not zero)
GWP: High
Problem: Still deplete ozone
Phase-out: 2020-2030
→
⚠️ HFCs
ODP: Zero ✅
GWP: Very High ❌
Problem: Climate bomb
Phase-down: Kigali
→
🟡 HFOs
ODP: Zero ✅
GWP: Very Low ✅
Problem: PFAS water pollutant ❌
Current frontier
→
✅ Natural
ODP: Zero ✅
GWP: Zero/Very Low ✅
No PFAS ✅
Ultimate solution
HFOs (Hydrofluoroolefins) — Complete Profile for UPSC
- What they are: A new class of refrigerants that contain at least one carbon-carbon double bond (unsaturated structure) — unlike HFCs which are fully saturated (no double bonds)
- Chemical significance of double bond: The double bond makes HFOs reactive in the lower atmosphere — they break down quickly (atmospheric lifetime of days, not decades like CFCs/HFCs). This short lifetime = very low GWP.
- ODP: Zero — contain no chlorine or bromine that could destroy ozone
- GWP: Very low — typically GWP < 1 (compared to HFC-134a's GWP of 1,430)
- Key examples:
- HFO-1234yf — replaces HFC-134a in automotive air conditioning (cars). Similar cooling performance. Formula: C₃H₂F₄. Being adopted by global auto manufacturers.
- HFO-1234ze — used in commercial refrigeration and foam blowing applications. Lower flammability than HFO-1234yf.
- Advantages: Zero ODP, very low GWP, similar performance to HFCs, compatible with some existing equipment
- Critical concern — PFAS: HFOs degrade in the environment into PFAS (Per- and Polyfluoroalkyl Substances) — specifically trifluoroacetic acid (TFA). PFAS are called “forever chemicals” — extremely persistent in water bodies, bioaccumulate in ecosystems, potentially toxic. Growing concern about long-term water pollution from HFO use. The Mongabay (2025) quote: “HFOs are not ozone-depleting and do not contribute to global warming, but they are water pollutants. Eventually, there will be discussions about phasing out HFOs as well.”
Natural Refrigerants — The Ultimate Sustainable Solution
- Ammonia (NH₃): Zero ODP, Zero GWP (GWP = 0). Excellent thermodynamic efficiency — actually more energy-efficient than HFCs. Used in large industrial refrigeration (cold storage, food processing). Disadvantage: toxic in high concentrations — not suitable for household use without containment systems.
- Carbon Dioxide (CO₂ / R-744): Zero ODP, GWP = 1 (the baseline!). Being adopted in supermarket refrigeration systems and automotive AC in Europe. Operates at very high pressures — requires different equipment design. Growing adoption globally.
- Hydrocarbons (Propane/R-290, Isobutane/R-600a): Zero ODP, very low GWP (~3). Excellent efficiency. Already widely used in household refrigerators globally (isobutane). Disadvantage: flammable — requires special handling and design. India is one of the leaders in R-290-based air conditioners.
- India’s pioneer status: India is among the first countries globally to use technologies that are both non-ozone depleting AND have low GWP — notably in R-290 (propane) based room air conditioners, developed under HPMP Stage II with MLF support.
5
India’s ODS Rules — Domestic Legal Framework
ODS (Regulation and Control) Rules 2000 under Environment Protection Act 1986
ODS Rules 2000 — Legal Structure
- Parent Act: Environment (Protection) Act, 1986 — ODS Rules issued under this Act
- Full name: Ozone Depleting Substances (Regulation and Control) Rules, 2000
- Nodal Ministry: Ministry of Environment, Forest and Climate Change (MoEFCC)
- Implementing body: Ozone Cell — established under MoEFCC as India’s National Ozone Unit (NOU); coordinates all ODS phase-out activities
- Ozone measurement: India Meteorological Department (IMD) is the nodal agency to measure ozone levels in India
- Key provisions:
- Prohibit production, import, export of specified ODS after cut-off dates
- Licensing system for remaining permitted ODS use (essential exemptions)
- Trade controls — ODS trade with non-Montreal Protocol parties prohibited
- Mandatory reporting by producers and consumers of ODS
- Mandatory registration for reclamation and destruction of ODS
- Amendments: 2014 amendment (added HCFCs), 2019 amendment (HCFC-141b ban), and further amendments for Kigali HFC controls (2024)
ODS Phase-Out Deadlines Under India’s ODS Rules
| ODS | Phase-out Deadline (India) | Exceptions | Status |
|---|---|---|---|
| Halons | After Jan 1, 2001 | Essential uses (aviation fire suppression) | Done ✅ |
| CFCs (Chlorofluorocarbons) | After Jan 1, 2003 | Pharmaceutical MDIs (metered dose inhalers) — phased out by 2010 | Done ✅ |
| CTC (Carbon Tetrachloride) | After Jan 1, 2010 | Feedstock use | Done ✅ |
| Methyl Chloroform | After Jan 1, 2010 | Feedstock use | Done ✅ |
| Methyl Bromide | After Jan 1, 2015 | Critical agricultural uses (with exemptions) | Done ✅ |
| HCFC-141b (foam sector) | Jan 1, 2020 | None | Done ✅ Pioneer achievement |
| HCFCs (new equipment manufacturing) | Jan 1, 2025 | Servicing existing equipment allowed until 2040 | Done ✅ (Jan 2025) |
| HCFCs (complete phase-out) | After Jan 1, 2040 | None after 2040 | In progress (HPMP Stage III) |
| HFCs (freeze) | 2028 (or 2030 if review triggers deferral) | India’s Kigali commitment | Future |
| HFCs (85% phase-down) | 2047 | From 2024–26 baseline | Future |
6
India’s ODS Phase-Out Journey — Achievements & Challenges
From global ODS user to pioneer in low-GWP technology — with a massive cooling sector challenge ahead
2001–2015
All Major ODS Phased Out
Halons (2001), CFCs (2003), CTC + Methyl Chloroform (2010), MDI-CFCs (2010), Methyl Bromide (2015). India phased out 9 of the 96 ODS it primarily produced/used.
Jan 2020
HCFC-141b Phased Out ⭐
HCFC-141b (used in rigid foam manufacturing) banned from import from Jan 1, 2020. India is 2nd largest producer/consumer of HCFCs globally. This pioneering achievement was among the first at this scale among Article 5 (developing) parties. 175 foam enterprises converted to low-GWP alternatives under HPMP Stage II.
Jan 2025
HCFCs in New Equipment ✅
All equipment and products relying on HCFCs for manufacturing phased out by Jan 1, 2025. Part of HPMP Stage II (2017–2024) completion. Stage III (2023–2030) now underway — targeting complete HCFC phase-out by 2030.
Jun 2024
HCFC Atmospheric Peak 5 Yrs Early
Nature Climate Change (June 2024): Global HCFC atmospheric concentrations peaked in 2021 — 5 years ahead of the targeted 2026. Direct proof that Montreal Protocol controls are working. Global HCFC EECl (Equivalent Effective Chlorine) declining from 321 ppt (2022) to 319 ppt (2023).
2023–2030
HPMP Stage III
HCFC Phase-out Management Plan Stage III — complete HCFC phase-out by 2030. Expected to reduce 19.24 million tonnes CO₂ equivalent from 2030 onwards. Includes servicing sector transition to HFC and natural refrigerant alternatives.
2028–2047
HFC Phase-Down (Kigali)
India’s HFC freeze: 2028. Phase-down: 10% (2032), 20% (2037), 30% (2042), 85% (2047). India’s cooling sector HFC demand projected to grow 9× — from 28,000 MT (2025) to 2,40,000 MT (2050). Massive technology transition challenge ahead.
🔴 2024 Bangkok COP/MOP — Latest International Development Current Affairs
- The COP 13/MOP 36 (2024) was held in Bangkok, Thailand — the combined Conference of Parties (Vienna Convention) and Meeting of Parties (Montreal Protocol)
- Key agenda items: HFC-23 emissions and data reporting; Long-Range Monitoring (LRM) of ODS; Very Short-Lived Substances (VSLS) potential ODS; feedstock exemptions; enhanced regional atmospheric monitoring
- Countries negotiated future solutions for cooling technology and energy consumption — how to achieve cooling access for growing populations while meeting Kigali targets
- Major focus: Avoiding import of energy-inefficient cooling products into developing countries — “leapfrogging” to high-efficiency, low-GWP technologies directly
- India’s position: Ensuring flexibility for its booming cooling sector while meeting Kigali commitments under Group 2 schedule
⭐ Complete ODS Measures Cheat Sheet
- Vienna Convention: 1985 | Framework only | Research + cooperation | No binding controls | India ratified 18 March 1991 | Secretariat: UNEP, Nairobi | 40th anniversary: 2025
- Montreal Protocol: Signed 16 Sept 1987 (= World Ozone Day) | In force 1 Jan 1989 | 198 parties | First universally ratified UN treaty | India joined 19 June 1992
- MLF (Multilateral Fund): Established 1991 | Article 10 of Montreal Protocol | Developed = DONORS | Developing = RECIPIENTS | US$4 billion+ disbursed | UNDP, UNEP, UNIDO, World Bank implement
- Key amendments: London 1990 (halons/CFCs out) | Copenhagen 1992 (HCFCs added, methyl bromide added) | 2007 (HCFC accelerated) | Kigali 2016 (HFCs)
- Kigali Amendment: Oct 2016, Rwanda | In force 1 Jan 2019 | 164 parties | Targets HFCs (zero ODP, high GWP) | Prevents 0.5°C warming by 2100
- India + Kigali: Ratified September 2021 | Group 2 | Baseline 2024–26 | Freeze 2028 (or 2030) | Phase-down: 10% (2032) → 20% (2037) → 30% (2042) → 85% (2047)
- HFOs: Hydrofluoroolefins | Zero ODP | Very low GWP | Contain double bonds (unsaturated) | HFO-1234yf (automotive AC) | HFO-1234ze (commercial refrigeration) | BUT: degrade to PFAS (water pollutants)
- Natural refrigerants: Ammonia (GWP=0), CO₂ (GWP=1), Propane/R-290 (GWP=3) | No PFAS | India pioneer in R-290 AC
- ODS Rules 2000: Under Environment Protection Act 1986 | MoEFCC (nodal) | Ozone Cell = NOU | IMD = measures ozone levels | Key bans: Halons 2001, CFCs 2003, Methyl Bromide 2015, HCFC-141b 2020, HCFCs in new equipment 2025
- India’s achievements: 2nd largest HCFC producer/consumer globally | Pioneer in low-GWP tech | HCFC-141b phased out 2020 (first at this scale among Article 5) | HCFCs in new equipment phased out Jan 2025
- HCFC atmospheric peak: June 2024 (Nature Climate Change): HCFC concentrations peaked in 2021 — 5 years ahead of 2026 target
- India cooling challenge: HFC demand for space cooling: 9× rise → 28,000 MT (2025) → 2,40,000 MT (2050)
- Bangkok COP/MOP 2024: COP 13/MOP 36 | Bangkok | Energy-efficient cooling, HFC-23 data reporting, VSLS, monitoring
🧪 Practice MCQs
Q1. Which of the following correctly distinguishes the Vienna Convention (1985) from the Montreal Protocol (1987)?
✅ Answer: (b) Vienna = framework; Montreal = binding controls
The key distinction tested repeatedly in UPSC: Vienna Convention (1985) is a framework treaty — it commits parties to cooperate, research, and share data on ozone depletion, but does NOT mandate any specific phase-out of any substance. It is the “agree to agree” foundation. Montreal Protocol (1987) is the binding implementation — it lists specific ODS, sets legally enforceable phase-out schedules with deadlines, establishes the Multilateral Fund, and creates a compliance mechanism. (a) Wrong: Vienna doesn’t target any substance; HFCs are addressed by the Kigali Amendment (2016). (c) Wrong: The Montreal Protocol is the universally ratified treaty (198 parties), not the Vienna Convention. (d) Wrong: The Multilateral Fund was established by the London Amendment to the Montreal Protocol (1990); the Ozone Secretariat (UNEP, Nairobi) serves both the Vienna Convention and Montreal Protocol.
Q2. Consider the following about the Multilateral Fund (MLF) under the Montreal Protocol:
1. It was established in 1991 under Article 10 of the Montreal Protocol.
2. Its purpose is to finance developing countries’ transitions away from ODS.
3. Developed countries are the recipients of MLF funding.
4. India has benefited from MLF for its HCFC phase-out programmes.
Which are CORRECT?
✅ Answer: (c) — 1, 2 and 4 only. Statement 3 is WRONG.
1 ✅: The MLF was established in 1991 under Article 10 of the Montreal Protocol (formally created by the London Amendment). 2 ✅: MLF’s purpose is to finance Article 5 (developing country) parties’ transitions away from ODS — covering technology transfer, training, industrial conversion. 3 ❌ Wrong — Classic UPSC Trap: Developed countries (non-Article 5 parties like USA, EU, Japan) are the DONORS to the MLF. Developing countries (Article 5 parties like India, China, Brazil) are the RECIPIENTS. This direction is frequently reversed in UPSC options. The logic: developed countries created the CFC problem through decades of industrial use; developing countries deserve financial support to transition without bearing those costs themselves. 4 ✅: India has been a major MLF beneficiary for its HCFC Phase-out Management Plan (HPMP) — Stages I, II, and III — receiving funds for converting foam manufacturing enterprises and refrigeration sectors to low-GWP alternatives.
Q3. Which of the following correctly describes India’s commitments under the Kigali Amendment to the Montreal Protocol?
1. India is in the Group 2 category of Article 5 developing countries.
2. India’s HFC phase-down baseline years are 2024–2026.
3. India’s HFC freeze year is 2028 (with possible deferral to 2030).
4. India will reduce HFCs by 85% from its baseline by 2047.
Select the correct answer:
✅ Answer: (d) — All four statements are correct
All four statements correctly describe India’s Kigali Amendment commitments: 1 ✅: India is in Kigali Group 2 — along with Pakistan, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, and UAE. These are countries with large cooling sectors and slower phase-down timelines than Group 1. China, Brazil, and South Africa are in Group 1 with earlier freeze dates (2024). 2 ✅: India’s HFC baseline = average HFC consumption for 2024–2026 + 65% of HCFC baseline. Using 2024–26 as baseline (instead of China’s 2020–22) gives India a higher baseline — recognising its later development stage. 3 ✅: India’s freeze year is 2028, with a condition: if a 2024–25 technology review shows cooling sector growth exceeded an agreed threshold, India can defer the freeze to 2030. 4 ✅: India’s phase-down steps: 10% by 2032 → 20% by 2037 → 30% by 2042 → 85% by 2047. India ratified Kigali in September 2021.
Q4. HFOs (Hydrofluoroolefins) are considered next-generation refrigerants. Which of the following is a CONCERN associated with HFOs despite their low ODP and low GWP?
✅ Answer: (c) — HFOs degrade into PFAS water pollutants
HFOs were developed specifically to address the twin problems of ODS (CFCs/HCFCs) and high-GWP greenhouse gases (HFCs). They succeed on both fronts: Zero ODP (no chlorine/bromine) and very low GWP (atmospheric lifetime of just days, vs HFC-134a’s 13 years). However, a new problem has emerged: when HFOs break down in the environment (especially in the lower atmosphere and water), they produce trifluoroacetic acid (TFA) — a type of PFAS (Per- and Polyfluoroalkyl Substance). PFAS are called “forever chemicals” because they are extremely persistent in aquatic environments, do not break down naturally, and are potentially toxic to ecosystems and human health. This concern is why some experts, including those cited in Mongabay’s 2025 analysis of India’s ODS journey, argue that HFOs are not the final solution either — and that natural refrigerants (ammonia, CO₂, propane) are the ultimate sustainable endpoint. (a) Wrong: HFOs have ZERO ODP — no ozone depletion. (b) Wrong: HFOs have very LOW GWP (typically < 1). (d) Wrong: HFO-1234yf is already widely used in automotive AC; HFO-1234ze in commercial refrigeration.
Q5. A June 2024 study published in Nature Climate Change reported a significant milestone related to HCFCs. Which of the following correctly describes this finding?
✅ Answer: (b) — HCFC atmospheric peak in 2021, 5 years ahead of 2026 target
This is a significant 2024 current affairs milestone directly relevant to India’s ODS story. The June 2024 study in Nature Climate Change reported: Global HCFC atmospheric concentrations peaked in 2021 — a full 5 years ahead of the 2026 target year. HCFC emissions have been on a declining trend since 2021. The direct radiative forcing from HCFCs declined from 61.67 mW/m² (2022) to 61.28 mW/m² (2023). The Equivalent Effective Chlorine (EECl) from HCFCs dropped from 321 ppt (2022) to 319 ppt (2023). This is direct observational proof that the Montreal Protocol’s HCFC controls are working faster than expected — the ozone-damaging chlorine from HCFCs is already declining in the atmosphere. This gives additional confidence that ozone recovery is proceeding on track. India’s parallel achievement: India phased out HCFCs in manufacturing new equipment by January 1, 2025, contributing to this global success. (d) Wrong: Full ozone recovery is not expected until 2040 (rest of world), 2045 (Arctic), and 2066 (Antarctica).
📜 UPSC Previous Year Questions (PYQs)
Which one of the following is associated with the issue of control and phasing out of the use of ozone-depleting substances?
✅ Official Answer: (b) Montreal Protocol
Montreal Protocol ✅ — signed 1987, specifically and exclusively targets ozone-depleting substances (ODS). 198 parties. First universally ratified UN treaty. Each trap answer is a real international environmental treaty: Minamata Convention ❌ — mercury pollution (named after Minamata disease, Japan). Kyoto Protocol ❌ — greenhouse gas emission reductions under UNFCCC (CO₂, methane, N₂O, HFCs, PFCs, SF₆). Note: HFCs are covered by both Kyoto (GHG) and Kigali Amendment (phase-down) — but the ODS treaty is Montreal. Nagoya Protocol ❌ — Access and Benefit Sharing of genetic resources under CBD. This question tests whether candidates can navigate between four real treaties on four different environmental issues.
“The Montreal Protocol has become both an ozone and a climate treaty.” Justify this statement. [Mains Angle — For Prelims practice on same topic]
With reference to hydrofluorocarbons (HFCs), which of the following statements is/are correct?
1. HFCs deplete the ozone layer.
2. HFCs are regulated under the Kigali Amendment to the Montreal Protocol.
3. HFCs are potent greenhouse gases with GWP much higher than CO₂.
✅ Answer: (c) — 2 and 3 only. Statement 1 is WRONG.
Statement 1 ❌ WRONG — The Single Most Important Fact About HFCs: HFCs do NOT deplete the ozone layer. They contain no chlorine or bromine. HFCs were developed specifically to REPLACE ozone-depleting CFCs and HCFCs. This is the foundational fact about HFCs and the most commonly tested UPSC trap on this topic. Statement 2 ✅: HFCs are regulated under the Kigali Amendment (October 2016) to the Montreal Protocol. Ratified by 164 parties. India ratified September 2021. Statement 3 ✅: HFCs are potent greenhouse gases — GWP ranges from 12 to 14,800 times CO₂ (depending on the specific HFC). HFC-23 has GWP of 14,800× CO₂. This is why Kigali targets them for climate reasons despite their ozone safety. Mains angle: Montreal is “both ozone and climate” because (1) ODS like CFCs are also GHGs — their phase-out prevented significant warming (135 Gt CO₂-eq avoided 1990-2010); (2) Kigali Amendment added HFCs specifically for their climate impact. Together they address both ozone depletion and a significant chunk of global warming.
In the context of WHO Air Quality Guidelines, consider the following statements:
1. The 24-hour mean of PM2.5 should not exceed 15 µg/m³ and annual mean of PM2.5 should not exceed 5 µg/m³.
2. In a year, the highest levels of ozone pollution occur during the periods of inclement weather.
3. PM10 can penetrate the lung barrier and enter the bloodstream.
4. Excessive ozone in the air can trigger asthma.
Which of the statements given above are correct?
✅ Official Answer: (a) 1, 3 and 4
Statement 1 ✅: WHO 2021 Air Quality Guidelines: PM2.5 annual mean ≤ 5 µg/m³; PM2.5 24-hour mean ≤ 15 µg/m³. These are stricter than India’s National Ambient Air Quality Standards (NAAQS) — India’s annual PM2.5 standard is 40 µg/m³ (8× more lenient). Statement 2 ❌ Wrong: Ground-level (tropospheric) ozone pollution is HIGHEST during GOOD weather — warm, sunny, still days with high solar radiation. Ozone forms from NOₓ + VOCs + sunlight (photochemical smog). Inclement weather (clouds, rain, wind) actually disperses ozone. Statement 3 ✅: PM2.5 (not PM10) penetrates the lung barrier and enters the bloodstream. PM10 penetrates deep into the lungs but typically does NOT cross into the bloodstream. However, as this was an official UPSC answer, UPSC appears to have considered Statement 3 correct for PM10 “penetrating the lung barrier” in the sense of reaching the alveoli — interpret as reaching deep lung tissue. Statement 4 ✅: Ground-level ozone is a known asthma trigger — it irritates airways, causes bronchoconstriction, and worsens respiratory conditions. Even at low concentrations, ozone exposure can trigger asthma attacks.
“The Montreal Protocol is considered the most successful multilateral environmental agreement.” Analyze the key factors behind its success. [Mains Format — 250 words]
For Prelims — Which of the following is NOT a factor in Montreal Protocol’s success?
✅ Answer: (c) — Voluntary pledges are NOT a feature of Montreal (that’s Paris Agreement/Kyoto)
This is a classic contrast question between Montreal Protocol’s success and the relative struggles of climate agreements (Kyoto/Paris). The key to Montreal’s success — and what distinguishes it from Paris/Kyoto: (a) ✅ Success factor: Universal ratification (198 parties) creates a genuine level playing field — no “free riders.” Every country faces the same basic framework. (b) ✅ Success factor: MLF financial mechanism makes compliance financially viable for developing countries — addressing the equity argument that derailed climate talks. (c) ❌ NOT Montreal’s feature: Montreal has BINDING, legally enforceable phase-out schedules — not voluntary pledges. This is precisely what makes it different from the Paris Agreement (which relies on Nationally Determined Contributions — voluntary). Montreal’s binding nature means non-compliance has real consequences (trade restrictions, naming-shaming in MOP). (d) ✅ Success factor: Quadrennial Scientific Assessment of Ozone Depletion guides policy. The SAP (Scientific Assessment Panel) provides independent scientific consensus, allowing the protocol to evolve as science improves (e.g., adding new ODS, adjusting phase-out timelines). The Mains answer should cover: Science basis, universal participation, MLF equity mechanism, trade restrictions for non-parties, binding controls, regular review mechanism, technology alternatives (unlike CO₂, ODS had readily available substitutes).
❓ Frequently Asked Questions
This comparison comes up repeatedly in UPSC Mains and is a favourite editorial topic. The key differences: (1) Binding vs Voluntary: Montreal has legally binding phase-out schedules with specific timelines. Kyoto had binding targets but only for developed countries. Paris relies entirely on voluntary NDCs with no binding emission targets — countries set their own. (2) Universal vs Partial participation: Montreal has 198 parties — universal. USA never ratified Kyoto; major emitters have repeatedly underdelivered on Paris commitments. (3) Equity mechanism: MLF specifically finances developing countries’ transitions. Climate agreements have struggled to operationalise climate finance — the $100 billion/year pledge is regularly missed. (4) Substitutes existed: For ODS, viable alternatives (HCFCs → HFCs → HFOs → natural refrigerants) already existed or could be developed. CO₂ has no direct substitute — entire energy systems must transform. (5) Industry alignment: Once alternatives were available and cheaper, industry supported Montreal compliance. Fossil fuel industries have actively resisted climate action. (6) Concentrated vs diffuse problem: ODS came from a small number of identifiable chemical industries. CO₂ comes from every sector of every economy — much harder to regulate. Bottom line: Montreal Protocol succeeded because it had the right institutional design (binding + equitable + science-based), solved a focused problem with available technical solutions, and built universal buy-in. Climate agreements face a fundamentally harder political and technical challenge.
This is a remarkable story of industrial transition under a regulatory deadline with financial support: (1) MLF support: The Multilateral Fund financed India’s HCFC Phase-out Management Plan (HPMP) Stages I and II — providing funds to ~175 foam manufacturing enterprises to convert their production lines to non-ODS, low-GWP alternatives. (2) Structured approach: MoEFCC’s Ozone Cell took a 3-part strategy: reduce demand through energy efficiency; replace HCFCs with low-GWP alternatives; use alternative technologies that don’t use ODS equivalents. (3) MSME focus: Most Indian foam manufacturers are MSMEs. Ozone Cell partnered with Central Institute of Plastics Engineering and Technology (CIPET) for technical hand-holding, training, on-site demonstrations, and product validation. (4) Regulatory clarity: The 2019 ODS Rules Amendment (banning HCFC-141b import from Jan 1, 2020) gave industry a clear, non-negotiable deadline — creating investment certainty for technology conversion. (5) Technology choice: India chose to adopt technologies that were not only non-ODS but also had low GWP — meaning the transition was both an ozone AND climate win simultaneously. This pioneering position — becoming one of the first Article 5 countries to phase out HCFC-141b at scale — enhanced India’s credibility in international negotiations and strengthened its position in Kigali talks.
Legacy IAS — UPSC Civil Services Coaching, Bangalore |
Sources: Mongabay India (January 2025) — India’s HCFC phase-out journey; NRDI India (December 2025) — India’s HFC Phase-Down Pathways (9× cooling demand projection); Nature Climate Change (June 2024) — HCFC atmospheric peak 2021; PIB (Sept 2021) — India Kigali ratification; UNEP Montreal Protocol official data (198 parties, MLF US$4 billion+); CDH IAS, NextIAS on ODS Rules 2000; MIT Press (Growing Apart: China and India at Kigali) for India Group 2 negotiation details; WMO Ozone Bulletin (2024) for 40th anniversary data.
