Which of the following causes water pollution?

When was the Water (Prevention and Control of Pollution) Act passed?

Which type of industries produce toxic substances and heavy metals as pollutants?

Domestic and hospital sewage often contains many undesirable pathogenic microorganisms. If discharged into water bodies without proper treatment, which of the following diseases can be caused?
$I-$ Dysentery or Diarrhoea
$II-$ Typhoid
$III-$ Hepatitis
$IV-$ Cancer
$V-$ Cholera
$VI-$ $AIDS$

What do you mean by Biological Oxygen Demand $(BOD)$?

Which of the following is more significant for water pollution?