Not possible.. Nuclear weapons are not the doomsday devices they are made out to be... Even a 1 megaton nuke kills almost everyone only Upto 10 km radius.. Pakistan population heat map shows population spread all along the Indus and tributaries in Punjab and Sindh, in cities, towns and villages.So, well over a thousand kilometers. Killing 75 percent of Pakistani population with the number of nukes India has is impossible.This is fouth such test to check the automated launch of multiple missiles to create an impact area. Long Back I had written about it to Late Parrikar who sent it to SFC. These test ensure that we can take out everyone in Pak Punjab within five minutes and kill over 75% of its population. This test is same as multiple round simulteneous impact (MRSI) used by artillery. The impact of both these missiles would have been at different places but simulteneously. In actual case, seven of them will be fired, six will be at 60* apart and one for the center. We need just 14x15KT nukes to take out Pakistan and kill over 75% of their population. Ewe need 34 of them to finish off over 90% of their poulation.
95 percent of China's population is present in 36 percent of China's landmass (east of the Heihe–Tengchong Line ).. This 36 percent is still huge, and as big as India. Besides, it is mountainous terrain, which limits the damage from nukes... All of 6000 American nukes can't kill 75 percent of chinese. Nukes are seriously highly overrated. That is why I laugh at apocalyptic nuclear scenarios. They will not come to pass. Nuclear war although destructive will not be the end of the world.. ( And nuclear winter apocalypse guys are more like climate change doomsday prophets)