Which of the following is a non-point source of water pollution?

Pollution is not caused by

Assertion : Organochlorine pesticides are organic compounds that have been chlorinated.
Reason : Fenitrothion is one of the organochlorine pesticides.

One of the human diseases due to biomagnification of heavy metals is

Select the correct option regarding algal bloom.
$I-$ Excessive growth of planktonic algae occurs due to the presence of high amounts of nutrients in water bodies.
$II-$ Algal bloom imparts a distinct color to the water bodies.
$III-$ Algal bloom causes deterioration of water quality and fish mortality.
$IV-$ All bloom-forming algae are highly toxic to humans and animals.

The process of aging of a lake by human activities occurs at a very rapid rate,which is called......