Researchers have found the first evidence that the thinning of the ozone layer above Antarctica is starting to heal, according to the BBC.

Observations and calculations indicate that, in September, the hole in ozone layer above Antarctica was around 4 million square kilometres smaller than it was in 2000. Four million square kilometres is roughly the size of India.

The study credits the gains to a long term ban on chemicals harming the ozone. The CFC chemicals compound that contains only carbon, chlorine, and fluorine, were globally banned in the Montreal Protocol in 1987. The situation in Antarctica has been slowly improving ever since.

According to US researcher Susan Solomon, there’s still a lot of chlorine left in the atmosphere, even though the production of the harmful chemicals was phased out in all countries, including India and China, around the year 2000.

"It (chlorine) has a lifetime of about 50-100 years, so it is starting to slowly decay and the ozone will slowly recover,” she told BBC.

"We don't expect to see a complete recovery until about 2050 or 2060 but we are starting to see that in September the ozone hole is not as bad as it used to be."

The ozone blocks out harmful ultraviolet radiation from the sun. The loss of ozone increases the chances of skin cancer, cataract damage, and harm to humans, animals and plants.