United Nation General Assembly declared September 16 as International Ozone Day for the preservation of the ozone layer. The ozone Layer is a shield located in the stratosphere of the earth and acts as a protecting shield against the ultraviolet radiations of the sun. The depletion of Ozone is caused by man-made chemicals that includes chlorofluorocarbons, halons, hydroflourocarbons, andmethyl bromide. These chemicals are widely used in refrigerators, air conditioners, fire extinguishers, in dry cleaning, as solvents for cleaning, electronic equipment, and as agricultural fumigants. Ozone is an unstable and reactive gas and because it is so reactive, the ozone in our atmosphere is very dynamic – it is being created and destroyed all the time. When UV light passes through the ozone layer, oxygen molecules are split up into their constituent oxygen atoms. These single atoms are then able to react with other oxygen molecules, forming ozone. But on other side these oxygen atoms also reacts with dangerous chemicals released from earth as well. The depletion of Ozone was observed in 1970’s and raised serious concerns all over the world. Realising the grave situation, the international community signed the Montreal Protocol on Substances That Deplete the Ozone Layer — an international treaty designed to protect the ozone layer by phasing out the production and consumption of a number of substances believed to be responsible for ozone depletion One of the major impacts of Ozone depletion is skin and lungdisease among human beings. These Ozone Depleting Substanceswhen released into aircombine with rain in air and results into acid rain. The acid rain hampers plants growth and causes corrosion of materials.The water of acid rain runs into lakes,river and sea and becomes fatal to marine life. The depletion of Ozone was observed in 1970’s and raised serious concerns all over the world. Realizing the grave situation, international community signed Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production and consumption of a number of substances believed to be responsible for ozone depletion. The treaty was opened for signature on September 16, 1987 and entered into force on January 1, 1989. Since then, it has undergone six revisions, in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), 1999 (Beijing) and 2016 (Kigali). Due to its widespread adoption and implementation it has been hailed as an example of exceptional international cooperation. Pakistan ratified the Vienna Convention, Montreal Protocol in 1992. Commonly used ODSs in Pakistan were chlorofluorocarbons (CFCs), halons, carbon tetrachloride (CTC), and methyl bromide. These ODSs were mainly used in the manufacturing of deep-freezers, refrigerators, foam blowing, fire extinguisher, process agents and solvents etc. Pakistan has successfully phased out the 1st Generation of ODSs and is now working on phase out of 2nd Generation of ODSs. In this regard 10% reduction target of 2nd generation of ODSs i.e. hydro-chlorofluorocarbons (HCFC) has been achieved by January 2015. Keeping in view Pakistan’s commitments to the international community, a National Ozone Unit under the project entitled “Institutional Strengthening of Ozone Cell for the Implementation of the Montreal Protocol” with the financial assistance of Multilateral Fund of the Montreal Protocol has been established under the mandate ofclimate change since January 1996. In Pakistan, many electronic brands have been introduced in markets that are environment-friendly products. The invertible air conditions available in market are energy efficient and protect the environment as well. As individuals, we need to analyze the cost and benefit while buying any electronic product. The products witha lower price, apparently compromise upon energy efficiency and damages the environment, so our individual decisions can have larger impacts on environment protection The writer is based in Islamabad and has done Masters in International relations from Quaid-i-Azam University Islamabad. She also completed an online course on environment Law and Policy from University of North Carolina,USA. Published in Daily Times, September 17th 2017.