Ozone day is

World Ozone Day was observed on..........

Ozone day, world Environment Day and National Pollution Preventation Day are celebrated respectively

Ozone day, world Environment Day and National Pollution Preventation Day are celebrated respectively

Ozone day, world Environment Day and National Pollution Preventation Day are celebrated respectively

Ozone day, world Environment Day and National Pollution Preventation Day are celebrated respectively

March 21 - World forest day April 22 - Earth day May 22 - International Ozone day June 05 - World environment day

About 20 m above the earth, there is an ozone layer. Which one of the following statement about ozone and ozone layer is true?