Why Holes In The Ozone Layer?

There is a drastic depletion of the ozone layer especially over the Antarctic. Why? Why only over the poles? This has been noticed since the eighties. Is this a natural climatic variation or a chemical decomposition? Is it due to the activities of humans? The actual still reason remains a mystery.
The reason has been proved scientifically that it is the reaction between chlorine and bromine emitted from industrially manufactured gases. But it is difficult to explain the depletion over the Antarctic due to these reasons since the emission of chlorine and bromine takes far away from the Antarctic.
It seems that the depletion of ozone over the Antarctic can be attributed to climatic changes that is occurring over the earth. Especially because of the lowering of temperatures across the earth. This, of course, is directly due to the effects of the gases produced by humans.
As such, we - the present generation - have to be particularly careful in the materials that we use so that we can leave a good legacy for our children. I would, in fact, say that we are living in the time that we have borrowed from our children.