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

Water pollution is best assessed by determining

The carrier of fluorosis is:

$(a)$ 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.

Match the following impurities in water with their respective categories:

Column-$I$	Column-$II$
$(P)$ Suspended solids	$(I)$ Fecal matter, bacteria, cloth and paper fibers
$(Q)$ Colloidal materials	$(II)$ Sand, silt, and clay
$(R)$ Dissolved materials	$(III)$ Nutrients (nitrate, ammonia, phosphate, sodium, calcium)

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
$VI-$ $AIDS$