Opposition to the construction of large dams is due to

List two main causes of the pollution of water of the river Ganga. State how pollution and contamination of river water prove harmful for the health of the people of neighbouring areas.

Compare the advantages of groundwater over water available from sources on the surface of the earth.

In our country,there are attempts to increase the height of several existing dams like Tehri and Almati,dams across Narmada. Choose the correct statements among the following that are a consequence of raising the height of dams:
$(i)$ Terrestrial flora and fauna of the area is destroyed completely.
$(ii)$ Dislocation of people and domestic animals living in the area.
$(iii)$ Valuable agricultural land may be permanently lost.
$(iv)$ It will generate permanent employment for people.

What is water harvesting? How can this technique help in the conservation of water?

Compare the water harvesting system used in hilly/mountainous areas with those used in plains or plateau regions.