Well here is what I think will happen:
1- China will start by launching a massive AI/Cyber attack on India's 3rd grade infrastructure. Within first 6-hours, most of indian civilian communication systems and essential infrastructure will stop working. Within 10 hours all Military communications will be dead.
2- Within first 6-hours, China will destroy all indian satellites.
3- Within first few minutes, China will launch 'Hypersonic' missiles at all Indian nuclear sites. Most of the indian nuclear sites will be destroyed. Those remaining will not be able to communicate.
4- Within first few minutes, China will launch 'Hypersonic' and other missiles to destroy most of indian storage facilities including fuel.
5- Within 24 hours, China will gain Air Superiority. Within one week, most of Indian Airforce will be destroyed.
6- Within 48 hours, all indian border military infrastructure will be destroyed.
7- PLA will then launch massive Ground and naval offensive. Within 48 hours, most of Northern india will be under the control of China. Within 7-days, New Delhi will be under the Chinese Control.
8- In Coordination with Pakistan, all J&K will be conquered by Pakistan along with Indian Punjab.
9- Chinese Naval forces will disrupt Indian Navy to the extent that it remains ineffective.
All in all, 70% of India will fall to China within 7 to 10 days.
