Source: https://www.mnn.com/earth-matters/space/stories/proof-ozone-hole-recovering

The ozone layer can be described as a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3) which absorbs 93-99% of the high frequency ultraviolet light coming from the sun, which is potentially damaging to life on earth. More than 91% of the ozone in Earth's atmosphere is present here. The ozone layer is mainly located in the lower portion of the stratosphere which is about 10 km to 50 km above Earth with a varying thickness depending on the seasons and geographical location.

 Source: https://www.mnn.com/earth-matters/space/stories/proof-ozone-hole-recovering

The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobson meter) that could be used to measure stratospheric ozone from the ground. The Ozone is formed by the buildup of oxygen in the atmosphere in the upper atmosphere or stratosphere. This forms a layer which filters out incoming ultraviolet (UV) rays which are very hazardous to man. While the oxygen (O2) we breathe consists of two atoms of oxygen bound together, Ozone, on the other hand, consists of three atoms of oxygen bound together (O3).  Though ozone can be found in the entire atmosphere, they are mostly produced naturally in the upper atmosphere or stratosphere.

 Source:https://steemit.com/introducemyself/@robus/ozone-layers-and-effects-of-its-depletion

 The ozone depletion is simply the destruction of ozone which is mainly caused by the release of human-produced chlorine and bromine compounds. Ozone depletion occurs when there is a destructive shift in the natural balance between the production and destruction of ozone in the stratosphere. Although natural processes can result to temporary ozone loss, chlorine and bromine released from man-made compounds such as chlorofluorocarbons (CFCs) have been discovered and now accepted as the main cause of this depletion. Drs. M. Molina and S. Rowland in 1974 were the first to suggest that an artificial group of compounds known as the chlorofluorocarbons (CFCs) were likely to be cause of ozone depletion. However, it was until the discovery of the ozone hole over Antarctica in 1985 by the Survey that the suggestion was taken seriously. Chlorofluorocarbons are compounds which are not dissolved and washed back by rain to the Earth or can be destroyed in reactions with some other chemicals. They simply do not break down in the lower atmosphere and they can remain in the atmosphere from 20 to 120 years or more. Due to their relative stability, CFCs are transported into the stratosphere where they are eventually broken down by ultraviolet (UV) rays from the Sun, thereby releasing free chlorine. The chlorine released becomes actively involved in the process of destruction of ozone. The ozone layer depletion has some damaging effects such as skin cancer and infectious disease, reduction of air quality, climate change etc.

International Actions

Ever since 1977, when a meeting of 32 countries in Washington D.C concerning World plan on ozone layer depletion was held, international actions and projects to focus attention on the dangers of ozone depletion in the stratosphere and its dangerous consequences have been carried out. In 1985, a protocol called the Montreal Protocol on Substances that Deplete the Ozone Layer was established and was signed by the European Economic Community in September, 1987 in other to phase down and phase out the use of CFCs, halons and other man-made Ozone-Depleting Compounds (ODCs). An agreement, where failure to comply would attract stiff penalties was made by the whole countries to reduce and eventually phase out altogether the use of CFCs and other ODCs.

 Also, the production and the use of eco-friendly compounds and methods to replace CFC compounds have been adopted. Hydrochloroflourocarbons (HCFCs) and Hydrofluorocarbons (HFCs) are now being used to replace CFCs in air conditioning and refrigeration.  In order to deal with the special difficulties experienced by developing countries it was agreed that they would be given an extended period of grace, so long as their use of CFCs did not grow significantly. China and India, for example, are strongly increasing the use of air conditioning and cooling devices. Using CFC compounds in these devices would be cheaper than using replacement compounds harmless to ozone.

 Personal Suggestion

Appreciating the numerous international actions and projects undertaken to control Ozone layer depletion, I would also like to suggest that the use of petrol-engine and diesel-engine vehicles should be globally discouraged. These vehicles release gaseous compounds that form smog which affects the ozone layer. The use of electric, hybrid or other vehicles with eco-friendly engines should be invented and internationally accepted.

Also, planting of trees at global level to reduce global warming is suggested

.The depletion of the ozone layer is a global problem which does not exclude any country or region. Therefore, international co-operation is highly recommended.

 Reference:

Sivasakthivel.T and K.K.Siva Kumar Reddy, Ozone Layer Depletion and Its Effects: A Review, International Journal of Environmental Science and Development, Vol.2, No.1, ISSN: 2010-0264; February 2011.