The size of the hole peaks towards the end of September because the hole has been in darkness now for six-month long Southern winter. The sun rises at the South Pole on September 23rd. As spring comes to the southern hemisphere the hole will shrink as the sun energizes the ozone layer.
We in the northern hemisphere go through this same media/government hysteria towards the end of March every year as the hole above the north pole.
Doesn't this suggest the hole is by the absence of local solar activity? --- and who cares what comes through the hole -- certainly not sunlight.
And the last I heard, there is a smoking volcano in Antarctica that contributes to the hole. I can't confirm that, but maybe somebody here can.