To you and all other alarmists shivering in fear over this:
0) Nothing ever happens. Nobody fired nukes over Cuba/Iran/Israel/Ukraine and DEFINETLY no one is willing to fire them over India of all fucking places lol.
1) In case nukes don't fly: it's just jeets killing each other. Good.
2) In case they do: why would the countries in question fire tactical nukes at any other country other than each other? Unless a third party DIRECTLY intervenes in this conflict (i.e. China declares war on India/US declares war on Pakistan), which is NEVER happenning, only tactical nukes will fly and only between the two countries involved. EVEN IF we assume some retarded impossible scenario occured and somehow India/Pakistan fired an ICBM towards China/the US, there is no reason for China/the US to unholster the strategical nukes to destroy the whole world instead of just firing tactical nukes back at India/Pakistan. To summarize: this is still just jeets killing each other but spicier, the world is not ending regardless of the outcome. Awesome.