New research published by the journal Nature sheds doubt on the optimistic conclusion that the ozone hole had recovered after suffering damage from man-made pollution. The study analyzed data from a NASA satellite mission launched in 2004 called the Aura Ozone Monitoring Instrument, which tracks atmospheric ozone levels at various altitudes over Antarctica. The researchers concluded that ozone levels have not recovered as much as previously believed. They explain that the ozone loss over the past two decades is likely more pronounced than generally accepted, and regional decreases in Antarctica during the winter and spring remain significant. The researchers note that further studies should be conducted to determine whether the ozone is indeed recovering, and if so, how quickly.