I doubt it will be a long and sluggish war. The war or more or less go like this ... below is an excellent post from a poster in another forum detailing what the initial stages of the war would likely look like if India attacked first (which is the more likely scenario). Once air supremacy is achieved, there would be virtually no chance for India to retain its defensive positions along the LAC as they would be under constant air and artillery attack 24/7.
I think this is a sign that China is getting serious and not just putting on a show. There would be little need to deploy JH7s otherwise, as they are very much the unglamorous workhorses of the PLAAF.
If the PLAAF was flexing for the cameras, they would be sent J16s. JH7s are for getting the job done while at the same time not placing anything too precious at higher risk.
As for air supremacy, well I don’t think the PLAAF will venture into Indian airspace in the event of combat, at least to start with.
The Chinese will focus on defence over Chinese airspace with fighters and SAMs complimenting each other while strikers and bombers spam cruise missiles form deep within Chinese airspace at Indian air bases, ground based early warning radar and other high value targets.
That puts the IAF in the impossible position of having to either pull back from most of its northern bases for fear of being obliterated on the ground, and gifting air dominance to China with a bow on top; or having to fight against overwhelming odds to try to get at Chinese bombers and strikers in Chinese airspace protected by layers of SAMs, AAA and having to fight through PLAAF fighter cap, which will almost certainly include J20s vectoring in from outside Tibet.
Forcing the IAF to fight over Tibet initially serves Chinese interests in multiple domains:
- it places the IAF at maximum disadvantage and allows the PLAAF to operate with home field advantage, which will more than offset any numerical and payload advantages the Indians enjoy due to geography.
- politically, it makes India the indisputable aggressor
- it makes it harder for India to BS away their losses as the Chinese would have actual physical evidence of shot down IAF planes and captured pilots.
Once China has cut the IAF down to size and reduced its northern air bases to rubble (via ballistic/cruise missile and air attacks), the PLAAF could then counter-attack into Indian airspace and take the fight to them and start to systematically destroy the helpless IA ground forces and any dual use pieces of infrastructure it feels necessary.
At that point it would not need to even fight very hard to achieve and maintain air dominance over huge sways of northern India.