China would destroy India with a limited conflict.If it came down to fighting, Pakistan will not hesitate to destroy itself fighting India. China will only fight a limited conflict.
Fight with China is going to be a mountain corps battle. Tanks are extremely hard to deploy in that region because of Himalayas.
Air power without land invasion army is worthless. Air power can only soften an enemy but to actually defeat an enemy, you need boots on ground.
China is limited threat to India because China is not desperate to fight India and India is well guarded against Chinese due to geography.
You should revisit Desert Storm. After 2 weeks of air power, there was little left on the ground and anything left had its engine turned off to avoid detection from the air, and was easy prey.