Montreal Protocol on Substances that Deplete the Ozone Layer

The Montreal Protocol on Substances that Deplete the Ozone Layer is an environmental treaty, which aims to protect human health and the environment by systematic phasing out of man-made chemicals that has adverse effects on the ozone layer. Signed on September 16, 1987, Montreal Protocol entered into force on January 1, 1989. Under this international treaty, countries around the world have carried out policies to reduce and eventually completely eliminate the emission of man-made ozone depleting substances.

Montreal Protocol


In 1970s, scientists proved that some man-made substances are responsible for the destruction of ozone layer in the atmosphere. This scientific confirmation raised the issue of emission of ozone depleting substances (ODS). It prompted the international community to react and establish a mechanism to protect the ozone layer through cooperation. As a result, the Vienna Convention for the Protection of the Ozone Layer, was adopted and signed on March 22, 1985. Through this convention, nations committed themselves to protect the ozone layer through co-operation and information sharing. Though it lacked definite measures or schedules to stop the use and production the ODS, it provided a framework for future protocols.

From September 14 to 16, 1987, a Conference on the Protocol on Chlorofluorocarbons to the Vienna Convention was held at the Headquarters of the International Civil Aviation Organization in Montreal, Canada. The conference was convened by the Executive Director of the United Nations Environment Programme (UNEP). Several countries participated in the Conference. India, including some other states, attended the conference as observer. On September 16, 1987, the last day of the conference, in pursuance with the objectives of Vienna convention for the protection of ozone layer, 24 countries agreed on the Montreal Protocol on Substances that deplete the Ozone layer. The protocol entered into force on January 1, 1989 and first meeting was held in May 1989 at Helsinki, Finland. Since then, the protocol was amended several times. India signed the protocol in 1992. Montreal Protocol achieved universal ratification in 2009.


The aim of the Montreal Protocol is to protect the ozone layer by taking measures to control total global production and consumption of ozone depleting substances and eventually eliminate them completely.

Go, the key objective of the protocol is to control and eventually phase-out the consumption and use of several groups of ODS. Those chemicals are classified according to the chemical family and listed in Annex A to Annex B of the treaty. For each group of chemicals, the Protocol provided specific phase-out timetables or schedules. Through the systematic phase-out, the protocol aims to cut down the emission of ODS and ultimately check the alarming rate of the depletion of the ozone layer.


The initial goal of the Montreal protocol was to reduce the production and consumption of CFCs and halons to 50% of 1986 level by 1999. But the developed countries phased out halons by 1994 and other ODS such as CFCs, carbon tetrachloride, and methyl chloroform by 1996. They also phased out methyl bromide by 2005. On the other hand, developing countries phased out halons, CFCs, carbon tetrachloride and methyl chloroform by 2010. Their methyl bromide phase out deadline was 2015. In 2010, the treaty started focusing on the hydro chlorofluorocarbons (HCFCs), which is used in cooling, refrigeration and manufacturing of foam products. Current goal of the treaty is to complete phase-out of HCFCs by 2030 in developed countries and by 2040 in developing countries. If the agreements under the Montreal protocol are followed in strictest sense, it is expected that the ozone layer will heal itself by year 2050.

Substances covered by Montreal Protocol:

Annex A – Group I: Chlorofluorocarbons (CFC-11, CFC-12, CFC-113, CFC-114 and CFC-115)
Annex A – Group II: Halons (halon 1211, halon 1301 and halon 2402)
Annex B – Group I: Other fully halogenated CFCs (CFC-13, CFC-111, CFC-112, CFC-211, CFC-212, CFC-213, CFC-214, CFC-215, CFC-216, CFC-217)
Annex B – Group II: Carbon tetrachloride
Annex B – Group III: 1,1,1-trichloroethane (methyl chloroform)
Annex C – Group I: HCFCs (consumption)
Annex C – Group I: HCFCs (production)
Annex C – Group II: HBFCs
Annex C – Group III: Bromochloromethane
Annex E – Group I: Methyl bromide

Multilateral Fund

For assistance in implementation of the Montreal Protocol, a Multilateral Fund was established in 1991. It was formed according to the decision of the meeting of the parties to the Montreal Protocol, which was held at London in June 1990. The main objective of the fund is to help developing countries to comply with the control measures of the Protocol. It offers assistance to those developing countries which are parties to the Montreal Protocol and whose annual per capital production and consumption of the ODS is less than 0.3 kilograms. Those countries are referred to as Article 5 countries. Currently there are 147 of them.

The Multilateral Fund is managed by an Executive Committee, consisting of equal number of members from both developed and developing countries. The source of the fund is the contributions from the member countries. Till 2015, around 45 countries had contributed over US$ 3.44 billion to this fund. The projects and activities under the fund are implemented through four implementing agencies. They are the United Nations Environment Programme (UNEP), the United Nations Development Programme (UNDP), the United Nations Industrial Development Organization (UNIDO) and the World Bank. The Secretariat of the multilateral fund is located in Montreal.

Achievements of the treaty:

The Montreal Protocol is one of the most successful international environmental agreements to date. In 1994, to commemorate the date of the signing of the protocol, the United Nations General Assembly proclaimed September 16 as the International Day for the Preservation of the Ozone Layer. Following are some of the key achievement of this ozone treaty:

  • The treaty attracted global participation. All member countries of the United Nations have ratified this treaty.
  • The protocol lead to the phase out of the consumption of about 98% of the ODS. By 2010, all countries had phased out the production and use of halons, CFCs, carbon tetrachloride and methyl chloroform.
  • With the help of the Multilateral Fund, developing countries were able to meet the phase out targets for various ODS.
  • Atmospheric levels of key ozone depleting chemical are going down. Now, ozone layer is expected to return to pre-1980 levels by 2050.
  • Many countries, both developed and developing, have met the phased out targets well before the deadline. This high compliance rate reflects the commitment of the international communities towards the protection of the environment.
  • By protecting ozone layer, Montreal Protocol is providing health benefits to the global community. It is lowering the risks of skin cancer and eye problems that arise due to exposure to UV radiation from Sun.
  • Through the reduction in ODS, which are also global warming gases, the Montreal Protocol is fighting against the problem of global warming.


  • United Nations Environment Programme,
  • Multilateral Fund,

Note: The information contained in this article is intended to be a helpful resource for your reference and it should not be relied upon for complicity.

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