The ozone layer is a part of high ozone concentration in the stratosphere, 15-35 kilometres above Earth's surface. The ozone layer performs as an invisible shield & protects us from harmful UV radiation from the sun. In particular, the ozone layer protects us from the ultraviolet radiation, known as UV-B, which causes sunburn. The long-term exposure to high levels of UV-B threatens human health and it damages most animals, plants & microbes, so the ozone layer protects all life on Earth.