According to NASA, the ozone hole reached its peak on September 11 which covered nearly an area about two and a half times the size of the United States.
This year's maximum is twice as big as the United States but is 3.37 million square kilometers smaller than last year and 8.5 million sq.
Warmer air temperatures high above the Antarctic led to the smallest recorded seasonal ozone hole in 30 years.
Newman said he and others at NASA don't fully understand why some years are stormier than others, and why ozone holes are smaller.
Thirty years ago, the worldwide community signed the Montreal Protocol on Substances that Deplete the Ozone Layer and began regulating ozone-depleting compounds.More news: Netanyahu meets May on Balfour centennial, addresses Iran, Palestinians
The treaty, known as the Montreal Protocol, has also helped save millions of lives, in addition to reducing the size of the hole.
The hole that hovers over Antarctica has been slowly recovering, scientists say, due to an worldwide ban on harmful chemicals that were previously used in refrigerants and aerosols. Clouds in this region are the sites where chlorine- and bromine-catalysed reactions take place and they destroy ozone molecules. The ozone hole reached its largest size in 2000 when it measured 29.86 million square km.
NASA scientists expect that the ozone hole will return to the 1980 levels sometime around 2070.
In spite of this recovery, the space agency mentions that there is enough ozone depleting material in the atmosphere to cause significant damage.
NASA and NOAA monitor the ozone hole via three complementary instrumental methods.
The Dobson spectrophotometer measures the total amount of ozone in a column extending from Earth's surface to the edge of space in Dobson Units, defined as the number of ozone molecules that would be required to create a layer of pure ozone 0.01 millimeters thick at a temperature of 32 degrees Fahrenheit at an atmospheric pressure equivalent to Earth's surface. On September 25, 2017, the concentration reached a minimum of 136 Dobson Units, the highest minimum since 1988. A lack of these clouds is one of the reasons why the ozone layer recovered strongly.