This season’s Antarctic ozone hole has swollen to an area of ten million square kilometres from mid-August – approximately the same size as Europe and still expanding. It is expected to reach maximum extent during September, and ESA satellites are vital for monitoring its development.
Full story:
http://www.esa.int/esaEO/SEM712A5QCE_environment_0.html
Although this story blames human activity for the Ozone Hole, we have only been able to measure the hole since the invention of the satellite. So, we have not been able to determine if the hole is part of a natural cycle of planetary existence.