International Day for the Preservation of the Ozone Layer is celebrated annually on September 16. It has been observed since 1994. It commemorates the day in 1987 when countries around the world signed the 'Montreal Protocol on substances that deplete the ozone layer'. Photo: AFP 

The 'Montreal Protocol on substances that deplete the ozone layer', commonly known as the Montreal Protocol, was put into place on September 16, 1987 and was formally acted upon on January 1, 1989. It involved the phasing out of every kind of substance that is responsible for the depletion of the ozone layer. In this photo, delegates attend the official opening of the 28th meeting of the Parties to the Montreal Protocol in Kigali on October 13, 2016. Photo: AFP

The ozone layer in the Earth's stratosphere helps to trap the UV light emitted by the Sun. The UV radiation is of two kinds - UVA and UVB - and both are known to harm humans by causing sunburns and skin cancers. Image for representational purpose only. Photo: istock

Among the many chemicals that cause damage to the ozone layer, the halocarbons which have bromine have higher ozone-depleting potential than those containing chlorine, according to the United Nations website. Some of the chemicals known to be harmful are chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) and methyl bromide. In this photo, an employee of Tradewater empties used refrigerants at the US company's plant to dispose off the CFCs from gas canisters. Photo: AFP 

The effectiveness of the Montreal Protocol led to it becoming one of only two treaties (the other being the Vienna Convention) to achieve universal ratification on September 16, 2009. The Montreal Protocol underwent an amendment on October 15, 2016 in Kigali, Rwanda, known as the Kigali Amendment, in an agreement among all the parties, to phase down hydrofluorocarbons (HFCs). In this photo, the president of the 28th meeting of the Parties to the Montreal Protocol and Rwanda's minister of Natural Resources Dr Vincent Biruta, hits a hammer as a symbol of the adoption of the Kigali amendment on October 15, 2016 in Kigali. Photo: AFP 

The 2022 theme for the International Day for the Preservation of the Ozone Layer is 'Global Cooperation Protecting Life on Earth'. According to the UN Environment Programme, the theme showcases the wider impact that the Montreal Protocol has on the environment and the need to collaborate, forge partnerships, and thus develop cooperation around the world to address these challenges and protect life on earth for future generations. Photo Courtesy: istock