Ozone Layer Protection

From signing to this year’s record closure

• 1987: the Montreal Protocol is signed by 46 countries, on 16 September 1987, to phase out ozone-depleting substances.
• 1992: full controls take effect. Ozone-hole recovery tracking begins from this year.
• 2021: India ratifies the Kigali Amendment on 21 September 2021, extending the Protocol to cover HFCs.
• 2025: the Antarctic ozone hole closes on 1 December, its earliest closure since 2019, and the fifth-smallest hole since 1992.

The Protocol’s record, and the recovery timeline

• The Montreal Protocol was signed on 16 September 1987, to phase out ozone-depleting substances like CFCs.
• Over 99% of controlled ozone-depleting substances have been phased out worldwide since then.
• The 2025 Antarctic ozone hole was the fifth-smallest since 1992. It closed on 1 December, the earliest closure since 2019.
• The ozone layer is projected to fully recover to 1980 levels: Antarctica by 2066, the Arctic by 2045, and the rest of the world by 2040.

The chemistry: how CFCs destroy ozone

• The culprits: CFCs, HCFCs, and halons are the main ozone-depleting substances. CFCs were once common in refrigerants and aerosol sprays; halons in fire extinguishers.
• These compounds are chemically inert in the lower atmosphere. That is exactly why they drift, unbroken, up into the stratosphere over years.
• Once in the stratosphere, intense UV radiation breaks these molecules apart, releasing free chlorine and bromine radicals.
• A chlorine radical rips an oxygen atom off an ozone molecule, forming chlorine monoxide and leaving ordinary oxygen. The chlorine monoxide then reacts with a second ozone molecule, releasing the original chlorine atom again.
• Because the chlorine atom comes out unchanged, it repeats this cycle. A single chlorine atom can destroy tens of thousands of ozone molecules before it is finally removed from the stratosphere.

HFCs, and India’s own schedule

• The Kigali Amendment (2016) added HFCs to the Protocol’s coverage. HFCs don’t harm the ozone layer, but they are powerful greenhouse gases.
• India ratified the Kigali Amendment on 21 September 2021.
• India’s HFC baseline is the average production and consumption across 2024, 2025, and 2026. A freeze at that level begins in 2028.
• After the freeze: 10% cut by 2032, 20% by 2037, 30% by 2042, and a cumulative 85% by 2047.

A treaty built to adapt, and India’s long runway

• Ozone protection and climate protection now run through the same treaty. Kigali turned a pure ozone agreement into a climate one too, since CFC replacements turned out to be potent greenhouse gases.
• The Protocol succeeded partly because it was built to be strengthened. Later amendments, like Kigali, could add new substances without renegotiating the whole treaty.
• India’s phase-down math gives industry a long runway. The baseline is set now, the freeze starts in 2028, and the final 85% cut isn’t due until 2047.
• For the mitigation-adaptation framework and the Kyoto Protocol angle, see EnvEco0002.

32nd World Ozone Day, 2026

• India marked the 32nd World Ozone Day in Mumbai on 16 September 2026, themed “Global Action for a Cooler Planet.”
• The Environment Ministry said India has exceeded its Montreal Protocol commitments without slowing its own development.
• India’s Net Zero Portal and NAPCC Dashboard were both launched on this same World Ozone Day.
• 248 ITIs were adopted by 12 refrigeration and air-conditioning manufacturers, to align technician training with industry needs. (Source: PIB)