The ozone hole is HEALING - and could soon close for good

Ozone layer sits in the stratosphere 25 miles above the Earth 's surface and acts like a natural sunscreen.

In 1985 , scientists discovered a 'hole' in the ozone layer over Antarctica that opened up during the austral spring , between September and December .

By 2016 there were key signs of ozone recovery, as the hole appeared to be shrinking with each year .

But it was unclear until now whether this was down to the reduction in CFCs or due to other influences such as El Niño , La Niña , and the polar vortex.

If the trend continues, there will be a year when there's no ozone hole depletion at all in the Antarctic .

The cause is not certain but the researchers believe it is possible climate change is altering the pattern of atmospheric circulation - causing more ozone to be carried away from the tropics. They say another possibility is that very short-lived substances (VSLSs), which contain chlorine and bromine, could be destroying ozone in the lower stratosphere. VSLSs include chemicals used as solvents, paint strippers, and as degreasing agents. One is even used in the production of an ozone-friendly replacement for CFCs..