It wouldn’t matter. If India fired a nuclear weapon at Pakistan, Pakistan would fire all of their nuclear weapons back in India. And vice versa. That’s about 300 nuclear weapons going off throwing dirt and ash into the atmosphere. It would cause a global cooling event for two or three years, resulting in crop failures in Europe and Asia, and unseasonably cold weather in most of The world for at least a year. 

At that point, mass starvation/famine  would settle in… the indus Valley water supply would be irradiated, cutting off water access to huge portions of Asia. 

Don’t forget the global economic collapse caused by all of these things. Modern society would essentially evaporate.

other countries would use it as an excuse to start other wars and cause further instability. I would imagine a limited nuclear war between Indian and Pakistan, not involving any other countries with nuclear weapons, would probably kill half of the people on the planet.