It is the second year running that the ozone hole has grown large enough to reach inhabited villages and towns in the southern hemisphere. Satellite measurements show that the hole itself is bigger and deeper than last year's previous record depletion.
The ozone layer protects people against harmful ultraviolet radiation, which can cause skin cancer and eye cataracts. Man-made pollutants in the form of chlorofluorocarbon gases are known to trigger chemical reactions in the atmosphere that destroy ozone, especially during the Antarctic and Arctic springs.
Nasa, the United States space agency, and the World Meteorological Organisation will publish readings from the Russian Meteor satellite that confirm ground-based measurements released last week by the British Antarctic Survey showing that the hole has never been deeper.
Rumen Bojkov, a special adviser on ozone at the WMO, said the hole - which officially occurs when ozone falls to 40 per cent of normal levels - appeared over the Falklands, 'a couple of towns in Argentina and several small villages in Chile' for two days.
Dr Bojkov said that over parts of Antarctica ozone levels fell to below 30 per cent of normal levels and more than 23 million square kilometres (about 9 million square miles) - an area the size of North America - had ozone levels below 40 per cent of normal.
Scientists warn that the ozone hole is likely to get worse before it gets better. CFCs are so long lasting that their effects are likely to continue long after their industrial production has ceased. The Montreal Protocol has so far only lessened the rate of increase in CFC production.
Earlier this year, scientists detected a thinning of the ozone layer over populated areas of the northern hemisphere; levels were about 14 per cent below average recorded for previous years.