Divert to Ganges and make it a sewage too?

This idea is bad in so many ways. It's gross hatred due to mass propaganda. First rule for sustainable water management is having local water supply used locally. We need better water management at individual city/village level like reviving lakes have a good ground water recharge etc.. Diverting rivers and desalination ideas are going to have huge ecological cost even if we forget about the economical possibility of them.

It turns out that Pakistanis are humans too, and they need water as well. Besides, there's the little problem of nukes.

Water

The reason Pakistan want Jammu-Kashmir, water security. China took Tibet, for a similar reason.

US wanted Gulf Oil; Invaded Iraq, what other countries after WW-II

Shit insecure bullies do to nurture their ego/fear.

Erm, that makes things worse in Pakistan. You do not want to destabilise an already unstable nuclear power.