Substantial Antarctic Ozone Hole in 2021 The 2021 Antarctic ozone hole reached its maximum area on October 7 and ranks as the 13th largest since 1979. Scientists from NASA and NOAA reported that this year’s ozone hole developed similarly to last year’s: A colder than usual Southern Hemisphere winter led to a deep and larger-than-average ozone hole that will likely persist into November or December. “This is a large ozone hole because of the colder-than-average 2021 stratospheric conditions, and