GENEVA: The Antarctic ozone hole has swelled this month to one of its biggest sizes on record, UN and US scientists say, insisting that the Earth-shielding ozone layer remains on track to long-term recovery but residents of the southern hemisphere should be on watch for high UV levels in the weeks ahead.

The World Meteorological Organisation, in a regular bulletin released on Thursday, said the Antarctic ozone hole often faces seasonal and year-to-year variations, but says the expansion this year shows "we need to remain vigilant".

The Geneva-based UN agency pointed to Nasa data on October 2 showing the hole had reached 28.2 million square kilometres - larger than the size of Russia and Canada put together.

Source: Times of India,29 October 2015