Earth.
Unprecedented Arctic Ozone Loss in 2011
Jet Propulsion Laboratory https://www.jpl.nasa.gov/ Oct. 3, 2011
A NASA-led study found that Earth's protective ozone layer above the Arctic thinned to the lowest levels ever observed in early 2011.
Transcript
A NASA-led study documented an unprecedented depletion of Earth's protective ozone layer above the Arctic last winter and spring, caused by an unusually prolonged period of extremely low temperatures in the stratosphere.
Ozone data from the Microwave Limb Sounder on NASA’s Aura spacecraft shows the depletion from January-March 2011 (purple in the polar region indicates most severe ozone loss).