As a whole (looking at the entire military infrastructure - conventional+unconventional/nuclear), India lacks a decisive edge to enter into a major conflict with Pakistan and emerge victorious and largely intact (Pakistan will suffer just as much). Having a deterrent is about discouraging the other party from entering into a conflict because the other party will suffer significant enough losses to overshadow any potential gains from said military conflict.
Pakistan has achieved that deterrence for the following:
1. Full scale war: A combination of conventional and un-conventional (nuclear) capabilities
2. Small scale conflict: Pakistan has enough conventional capabilities that India cannot do another Siachen or Pakistan version of Kargil because to do so would result in escalation (see point one).
Now whatever spin you want to put on India's inability to escalate a military conflict with Pakistan, despite a plethora of hysterical, war mongering statements from the BJP government and Indian military, the fact is that India lacks the capabilities for a decisive victory over Pakistan without suffering horrible losses herself. Those potential losses are, at the moment, too significant to justify any kind of military conflict with Pakistan - deterrence.