There's still a considerable hole in the Antarctic ozone layer, say scientists, with this year's peak the ninth largest in the 26 year record.
It's a disappointment, given that this time last year a UN study found that the layer was regenerating.
However, say NASA and the National Oceanic and Atmospheric Administration (NOAA), today's announcement may not show that last year's conclusion was wrong.
"The colder than average temperatures in the stratosphere this year caused a larger than average ozone hole," says Paul Newman, chief scientist for atmospheres at NASA's Goddard Space Flight Center.
"Even though it was relatively large, the area of this year's ozone hole was within the range we'd expect, given the levels of manmade ozone-depleting chemicals that continue to persist in the atmosphere."
The Antarctic ozone hole, which expands every Southern Hemisphere spring, reached its annual peak on September 12. It stretched to 10.05 million square miles. Above the South Pole, the ozone hole reached its deepest point of the season on October 9, tying this year for the 10th lowest in this 26-year record.
"The manmade chemicals known to destroy ozone are slowly declining because of international action, but there are still large amounts of these chemicals doing damage," says James Butler, director of NOAA's Global Monitoring Division.
A recent NASA study found that a significant hole had opened up in the ozone layer over the Arctic for the first time.