As the word suggests, Ozone depletion is the lowering of the ozone due to chemical pollution in the stratospheric layer of the Earth.

Ozone is basically a gas in the atmosphere that protects everything living on the Earth from harmful ultraviolet (UV) rays from the Sun. Without the layer of ozone in the atmosphere, it would be very difficult for anything to survive on the surface. In simpler words Ozone layer acts like a filter to protect our earth against the shorter wavelength and highly hazardous rays of sun.

When CFCs reach the stratosphere, they are exposed to the Sun?s UV radiation, which causes them to breakdown into substances including chlorine which react with ozone  to form oxides which combine with sunlight to destroy ozone.

Usage of aerosol largely affects the ozone layer because most aerosol cans have chlorofluorocarbons or CFCs, and CFCs are the biggest ozone depleting substance. It's best to avoid using them to protect the environment.

The destruction of the ozone layer has been particularly prominent over the Antarctic. The low temperatures in the region produce polar stratospheric clouds, which enhance free chlorine through chemical reactions on the cloud surfaces. This, in addition to the long periods of sunshine during the spring and summer seasons, has caused up to 65% of the ozone to be destroyed, compared to 20% in the Arctic and about 5-10% in other world regions.

Many people were worried about the depletion of the ozone layer and the implications this could have for human health. In 1987 an international agreement to protect the ozone layer, called the Montreal Protocol, was signed by 24 countries and by the European Economic Community in September 1987. The Protocol called for the Parties to phase down the use of CFCs, halons and other man-made ODCs.

 This agreement has led to a reduction in the release of CFCs into the atmosphere. The Montreal Protocol was the first treaty in history to achieve universal ratification – meaning that it has been ratified by every member state of the United Nations. Its success has led to the recovery of the ozone layer over Antarctica and less ozone depletion worldwide in the past few years. The long atmospheric lifetime of CFCs mean that it could be 2060 or 2080 before the damage is fully repaired, but the swift action taken at an international level has helped to avoid a global catastrophe.

 As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2050 and 2070.  Due to its widespread adoption and implementation it has been hailed as an example of exceptional international co-operation, with Kofi Annan quoted as saying that "perhaps the single most successful international agreement to date has been the Montreal Protocol".

 As part of its efforts to protect the ozone layer, the UAE is also a signatory to Montreal Protocol  and has taken many steps, in line with its commitment. UAE has set up procedures regulating the use of substances that deplete the layer. It has levied fees on issuance of license to import harmful substances. UAE is shifting to alternative substances.

Credit-  Wikipedia, royal society.org