Hardened shelters is one answer....atcs will be tricky but the biggest deterrent is instant reaction across the border which means prioritizing targets way before any incident that need to be hit
Sensible suggestion.
Now we know that the Pakistani security/military establishment will never totally cease anti India activity. If not military targets then economic targets will be hit in India.
Now we have a system of classification of cyclones and hurricanes. Depending on the severity of the cyclonic system taking into consideration factors like wind velocity, extent of cloud cover etc we grade the threat into 3 categories
1.Red Alert (highly destructive)
2.Orange Alert (moderately destructive)
3.Yellow Alert(mildly destructive)
Similarly we need to have an classification of the destructive activities of the ISI.
1.Red Zone.
Very major attacks like the Parliament attack, Mumbai bomb blasts after the
Babri Masjid demolition, Pulwama attack etc.
2.Orange Zone.
Major attacks like the Mumbai train bombing, Uri attacks etc
3.Yellow Zone.
Significant impact attacks like the Coimbatore bombing, Jaipur bombing etc.
The grading of the severity of the provocation from Pakistan is open for debate.
The list of attacks mentioned is very, very small and not exhaustive. It has not included economic sabotage by the ISI.
Now we need to have an list of all possible targets in Pakistan including economic.
The targets in Pakistan can be classified into 3 categories like Red, Orange and Yellow based on their importance. The list will probably run into thousands of targets.
Now based on the severity of an ISI attack which takes place in India we should choose an equivalent target in Pakistan for reprisal. Example if an category Red, a major attack takes place in India we already have a list of Red category targets in Pakistan probably running into the hundreds or thousands. Our security people can choose the most appropriate Red category target in Pakistan based on our assets in Pakistan and the geo political situation. So the task of searching for suitable targets in Pakistan is made easier and fast.
Even if the list of probable targets information is leaked to Pakistan there is no way they can ensure the security of thousands of potential targets on a 24hrs,365 days basis. Only if they can pinpoint the target chosen by India they can try to prevent an attack.
Probably such an list already exists in India.