The gas emitted by supersonic jet planes that slowly depletes the ozone layer is

The pH of normal rain water is

The process of 'eutrophication' is due to

Excess nitrate in drinking water can cause

The maximum prescribed concentration of cadmium in drinking water in ppm is

Which of the following is true about photochemical smog?

The smog is essentially caused by the presence of

London smog is found in

Photochemical smog is formed in

Depletion of ozone layer causes