A layer in the earth’s stratosphere at an altitude of about 10 km (6.2 miles) containing a high concentration of ozone, which absorbs most of the ultraviolet radiation reaching the earth from the sun.
Why this ozone layer is important?
The ozone layer is a natural layer of gas in the upper atmosphere which protects humans and other living things from the harmful ultraviolet (UV) rays of the sun.
September 16 was designated by the United Nations General Assembly as the Ozone Layer. This designation had been made on December 19, 2000, in commemoration of the date, in 1987, on which nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer. This day is observed to recall the importance of it as well as to preserve it.
Source: Shyamala Subarna
