The ozone hole is the region of severe seasonal ozone depletion over Antarctica identified in the 1980s.
Scientists at the British Antarctic Survey reported the discovery in 1985 after measurements showed that Antarctic spring ozone levels had fallen dramatically. The depletion is driven by chlorine and bromine compounds released from human-made chemicals such as chlorofluorocarbons.
During the dark polar winter, extremely cold stratospheric clouds help convert these compounds into reactive forms. When sunlight returns in spring, chemical reactions destroy ozone rapidly. The polar vortex helps isolate the air above Antarctica.
The ozone hole is not a literal empty gap and is not the same as climate change. The Montreal Protocol, agreed in 1987, phased out many ozone-depleting substances, and the ozone layer is expected to recover gradually.