Ozone Secretariat, United Nations Environment Programme

Rule Changes

Administers the Montreal Protocol and publishes annual Antarctic ozone bulletins

On September 18, the hole in the ozone layer over Antarctica covered 10.5 million square miles, about 90% of the largest single-day extent ever measured. Averaged across the peak depletion season from September 7 to October 13, it was the seventh-largest hole in 48 years of satellite records.

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