I will come back to the success of the Montreal Protocol.
This is what the scientists know, that the depletion of ozone was caused by ozone-depleting substances. The goal of the Montreal Protocol was to ban the production and use of ozone-depleting substances. It has been very successful. We know from inventories taken around the world that ozone-depleting substances are, to a large extent, no longer used.
There is already scientific evidence that the situation with the ozone layer has improved, but scientists are always garnering new findings. Now there is also interest about the interaction between ozone and climate change, so another reason for measuring ozone has come to light. But again, this is at a large global level, not at a “specific point in geography” level.