question_answer 37)

  Ozone layer is getting depleted because of (a) excessive use of automobiles (b) excessive formation of industrial units (c) excessive use of manmade compounds  containing both fluorine and chlorine (d) excessive deforestation

Answer:

  (c) Reduction in the concentration of ozone layer is called ozone depletion. It is caused by certain chemicals which are generally rich in some of the chlorine, fluorine and carbon and are called Ozone Depleting Substances (ODS). Some of the important ODSs are chlorofluorocarbons  haloes, methyl bromide, nitrogen oxides and Carbon Tetra Chloride and dichlorodifluoromethane  CFCs are commonly used as aerosol propellants, refrigerants, shaving foams, spray agent in scents, etc. Some ODS are released in the stratosphere by jets flying at height.