How is the ozone created and disappearing

What is the ozone?
Ozone is a gas composed of three oxygen atoms (O3). It is formed naturally in the upper levels of the earth's atmosphere by high-energy ultraviolet radiation from the sun. The radiation breaks down oxygen molecules (O2), releasing free atoms (O), some of which bond with other oxygen molecules to form ozone (O3).
Ozone atom About 90 % per cent of all ozone in the atmosphere is formed in this way, between 15 and 55 kilometers above the earth's surface - the part of the atmosphere called the stratosphere. Hence, this is known as the "ozone layer."
 
 
The ozone layer is a term used to describe the presence of ozone molecules in the stratosphere.
The ozone layer is vital to life on the surface of the planet. It acts as a filter and prevents the harmful ultraviolet radiation (UV-B) from reaching the Earth.
 
 
 
Depletion of the ozone layer will lead to the reduction of its shielding capacity and thus an increased exposure to the UV-B radiation, which can have the consequences on humans (skin cancer, eye cataracts, sunburn, snow blindness, skin aging, and depression of the immune system); the aquatic ecosystem (limits the production of phytoplankton and causes damage to the early developmental stages of fish, shrimp, crab, amphibians, and other sea creatures); terrestrial plants (affect their growth); materials used in buildings, paints, packaging.
 

What is the ozone hole?
The ozone "hole" is really a reduction in concentrations of ozone high above the earth in the stratosphere over the Antarctic. First time ozone hole was discovered at 1985.