People did not discover about it, scientists did. They did it in 1985.
Ozone layer is a protective layer. The problem with it is its depletion.
Nothing is wrong with ozone layer. There is problem with absence of ozone layer.
They did it in 1880. It is a layer of ozone molecules.
The main problem with ozone layer is the depletion. It is due to the reckless use of CFC's by humans.
The problem of ozone layer is worsening. It is due to many ODS working together.
Ozone is depleting. It is due to CFC's.
Poking holes in ozone layer is a problem. A hole in ozone would cause the ultraviolet radiations to enter the surface.
The ozone layer is breaking. It is because of the use of CFC's by humans.
People do have problems with ozone layer. But the problems are invalid as the ozone protects us.
There have been hundreds of ozone layer slogans in the past several years. There are many groups who are concerned about damage to the ozone layer and their campaigns and strikes have brought the problem to the attention of many other people.
CFC's cause problems to ozone layer. They help in its depletion.
Ozone layer is decreasing. It is because of CFC's that are depleting it.