The insecticide $DDT$ is considered as . . . . . .

Which of the following is responsible for the depletion of ozone in the stratosphere?

Which of the following statements is $NOT$ true about acid rain?

The greenhouse effect is responsible for global warming. Which gases are responsible for the greenhouse effect?

$A.$ Ammonium salts produce haze in the atmosphere.
$B.$ Ozone is produced when atmospheric oxygen reacts with chlorine radicals.
$C.$ Polychlorinated biphenyls act as cleansing solvents.
$D.$ 'Blue baby' syndrome occurs due to the presence of excess nitrate ions in water.
Choose the correct answer from the options given below:

Excess of which of the following in water causes blue baby syndrome disease?