The World Meteorological Organization says that a record loss of ozone -- the atmosphere layer that shields the Earth from the Sun's harmful ultraviolet rays -- has been observed over the Arctic in recent months.
The United Nations' weather agency said the ozone layer over the Arctic region has suffered a loss of about 40 percent from the start of winter till late March, exceeding the previous seasonal loss of about 30 percent.
The agency blamed the loss on the continuing presence of ozone-depleting substances and on a very cold winter in the stratosphere.
A UN treaty, known as the 1987 Montreal Protocol, has resulted in cutbacks in ozone-damaging chemicals but it will take decades before their concentrations in the atmosphere decrease.
The compounds were once used as coolants in refrigerators, air conditioners, and even hairspray.
compiled from agency reports