The hole in the ozone is 25 years old. At the recent 20th International Ozone Symposium, held on Kos, scientists from 60 countries declared the ozone layer over the Mediterranean to be stabilizing, the problem over the Antarctic to be as bad as ever, and announced new data on how the hole is created. At the same time, according to a report by the European Academy’s Science Advisory Council (EASAC), levels of atmospheric pollution remain high in Europe because of the air pollution from North America and Asia. Following the signing of the Montreal Protocol in 1987, which banned the substances responsible for the destruction of the ozone layer, the ozone hole over the Mediterranean appears to be stabilizing, the symposium heard. However, this is most probably due to the «strange» climatic conditions prevalent lately and not to the effectiveness of the measures taken. In addition, a new ozone-depleting mechanism has been discovered which is linked to meteorological changes. According to the general secretary of the International Ozone Commission, Christos Zerefos: «Human beings have destroyed in 25 years as much ozone as nature has made in billions of years,» and he said the phenomenon needs to be closely monitored. There is also bad news on the air pollution front in Europe. Average annual concentrations of surface ozone – which is an atmospheric pollutant, unlike the protective layer high above the Earth – in some EU countries, including Greece, are approaching health and safety limits as a result of pollutants drifting in from other parts of the northern hemisphere. According to Professor David Fowler, «the EU cannot deal with the problem of atmospheric pollution alone.» These findings are contained in the Athens Decision, signed by representatives of all European academies, calling on politicians to take action in accordance with new scientific data.