According to data from the agency's Envisat satellite, the South Pole's ozone layer has lost approximately 27.7 million metric tons this year, compared to 2006's record of 40 million metric tons.
The size of the hole is now estimated at 24.7 million sq km (15 million sq miles) - equivalent to the size of the North America - against 29.5 million sq km (18 million sq miles) last year.
"Although the hole is somewhat smaller than usual, we cannot conclude from this that the ozone layer is recovering," the press release quotes a senior project scientist at Royal Dutch Meteorological Institute, as saying.
He explained the phenomenon by the fact that this year's hole was less centered on the South Pole, and that the inflow of warm air which prevents the ozone from depleting was more intensive.
The ozone hole, first recognized in 1985, occurs during the Antarctic spring, from September to November or December. The overall cause is chlorine-containing gas that in sunlight splits into highly ozone-reactive radicals and breaks ozone down into individual oxygen molecules. One molecule of chlorine can theoretically split thousands of ozone molecules.
