Let me set some expectations right in this thread.
You are not going to beat Pakistan with economic warfare. Pakis run on credit lines, and any economic damage you inflict will be part of their next bheek application to Beijing or Washington, which will be promptly granted. You are not trying to wage economic war against the paki exchequer but the chicom/wignat exchequer--it's like pissing against the wind.
An erratic water supply means failed crops, which could cause some domestic political upheaval, because bheek will import food from the world food markets (there's plenty of food in the world); but the paki feudal farmer will have lighter wallets. Pakis have a very similar feudal farming system to the arthiyas of Indian Punjab. The trickle down of that bheek to peasants under each feudal farmer will be much less.
Pakistan stopped being a conventional adversary as of 1971, it is fighting textbook Islamic war. Losses are not measured in lives but territory. Pakis could attempt to encroach India, get pushed back, but as long as they're pushed back to the status quo (LC/WB/IB, whatever), the attempt is never written as a defeat in their books, no matter how many lives were lost.
The only real damage you can cause to pakis is loss of territory. Loss of territory, especially in a war they started, would have a devastating impact on the hukumat. When pakis lost territory in 1971, it was a bloodbath in West Pakistan for almost the entire decade of the 1970s--jernails and feudal families, everyone lost lives (Zia, Zulfikar Bhutto, you name it).
Any Indian response to a conflict pakis started should aim to grab territory, however small that might be, even if it means smoothing out bulges along the LC. Those dumbasses practically handed this option to us by walking away from Simla Agreement. Even telling pakis "hey look, these are the peaks and bulges we grabbed," would devastate their morale, no amount of retorting with losses of life on the Indian side will hide their cope. Establishing loss of territory as a new normal for paki gandmasti would have a deterrent effect like no other.
For there to be any meaningful peace in Kashmir, both pakis the local kashmiris need to be told that India has complete area domination, and all of their acts will be invoiced--payable in territory.
All that said, I have no clue what India is planning. Paki mobilisation is aimed to create a Parakram-like stalemate, which means at some level they realise India is going to tug at the LC and IB.
There are two factors that pakis are overplaying, exactly because they are overrated:
1. Nukes
2. Chicoms
Nukes--pakis are not going to nuke us over any ingress we make into PoK. No elaboration needed. Even the looniest mulla holding the nuclear trigger knows that starting a nuclear exchange over Kashmir only causes them to haemorrhage territory.
Chicom intervention--they will not start a hot war on paki's behalf, they will try to build-up and try to stimulate a mirror mobilisation on the Indian side that stretches Indian force thin on two fronts, but this will not result in a hot war. Chicoms swapped out at least 3 known theater commanders and had to bring in central theater command troops during Galwan. They do not dominate anything in that front.