1. Construction of dams and barrages on rivers
2. Increase in the population of crocodiles in rivers
3. Getting trapped in fishing nets accidentally
4. Use of synthetic fertilizers and other agricultural chemicals in crop-fields in the vicinity of rivers
Select the correct answer using the code given below.
Correct Answer: (c) 1, 3 and 4 only
Solution:The construction of dams and barrages on rivers, getting trapped in fishing nets accidently and use of synthetic fertilizers and other agricultural chemicals in crop-fields near the rivers are the reasons for the decline in the population of Ganges river Dolphins.