Lets understand that war is not an easy option specially when your opponent is nuclear state. And nothing can be more dangerous then a isolated nuclear state in a case of war. Now even if we assume that war is the necessity then it requires planning and preparation at the ground (imagine in case of 1971 India took 6 month to plan before we could proceed). So even if there is something like this is going on then you will get to know after six month only.
Let lets consider the surgical strike option - via AF or Missile or crossing the troops on LOC, all three are very risky operation as all can result into full scale war for which defense needs to be prepared in advance.
So the best option for any government is to hit economically by isolating them, hitting their economic interest and may be blocking the water could be a other possible option (I dont know the conditions of IWT is it binding or not or if we break from the treaty then what are the possible outcome at the internation level).
So my take is to start building the dams on Jhelum, Indus and Chenab with the whole purpose of these dam should be to tactical blocking of the water. And attach water availability with the terror at the ground level.