UPSC Civil Services Model Paper 4

No study cites heat pollution of water and industrial effluents as a problem for the Gharial population . So, statement 2 and 3 are NOT correct.
Below, all the major causes are listed.
It has been picked from IUCN's website.
Their population decline can be attributed to a variety of causes including over-hunting for skins and trophies.
egg collection for consumption killing for indigenous medicine killing by fishermen (for example Biswas 1970 and Whitaker 1975).
While hunting is no longer considered to be a significant threat, the construction of dams, barrages, irrigation canals, siltation, changes in river course, artificial embankments, sand-mining, riparian agriculture, and domestic and feral livestock have combined to cause an extreme limitation to gharial range due to this excessive, irreversible loss of riverine habitat.