Air pollution has several effects on all living organism and on climate. Diseases like bronchitis, lung cancer and emphysema are caused by air pollution (i) $NO_{2}$ causes bronchitis and lowers the resistance to influenza (ii) $SO_{2}$ obstructs breathing and irritates eyes (iii) Nitric acid, nitrous acid and sulphuric acid causes respiratory diseases Air pollutants reduce growth and yield of crops and cause premature death of plants