Why is ozone considered a pollutant in the ozone layer?

Ozone in the ozone layer is not at all a pollutant but it is something without which no ozone layer may have existed. Ozone can be considered as a pollutant in the stratospheric region but in the stratosphere or the ozone layer it is of full or complete use. No harms there.
Ozone in the ozone layer is not at all a pollutant but it is something without which no ozone layer may have existed. Ozone can be considered as a pollutant in the stratospheric region but in the stratosphere or the ozone layer it is of full or complete use. No harms there.