Which method is used by municipalities in cities to treat wastewater?

How can water pollution be measured?

When can it be said that the level of pollution in water is high?

$(a)$ Discuss the major programs that the Ministry of Environment and Forests,Government of India,has initiated for saving major Indian rivers from pollution.
$(b)$ Ganga has recently been declared the national river. Discuss the implication with respect to pollution of this river.

Which of the following is a main factor of water pollution?

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
$VI-$ $AIDS$