Which are the primary constituents of photochemical smog?

What percentage of forest cover for hills has been recommended by the National Forest Policy $(1988)$ of India (in $;\%$)?

$A$: Polyblend is a fine powder of recycled modified plastic.
$R$: The blend of polyblend and bitumen helps to increase road life by a factor of three.

Which act was enacted by the Government of India to protect and improve the quality of our environment and to control environmental pollution?

Which one of the following is not related to $5\; F's$ of the Chipko movement?

Identify the correct statements from the following:
$(i)$ $DDT$ is non-biodegradable.
$(ii)$ Heavy metals are responsible for biomagnification.
$(iii)$ High concentration of $DDT$ disturbs calcium metabolism in birds.
$(iv)$ The concentration of $DDT$ in large fish can be up to $2 \, ppm$.