OZONE, a form of oxygen, is found in a layer that begins about 10 km (six miles) from the Earth and extends to 48 km above the Earth's surface.
It acts as a shield to protect the Earth from the sun's damaging ultraviolet rays, which are the rays you can't see but which are so strong they can damage the skin and eyes.
There are no actual holes in the ozone layer, just places where the amount of ozone in the atmosphere is very small at certain times of the year.
In recent years, one such thin spot has been appearing over the South Pole. It shows up for a few months, then goes away.