Question

Where did the people of India and Bangladesh rely on to get water decades ago? What was the issue with this?

Answer 1

The rivers, so mainly the river Ganges

Explanation:

This was the closest water source for most. The problem with this is it is holy water to Hindus so it is sacred to wash in it or drink it and the water is very unsanitary for this reason. Also, people wash clothes and dump waste in the river... And I don't just mean wrappers. So to sum it up, the rivers was often the best source of water and it was unsanitary due to the other uses of this water.
Hope this helped.