ON TOPIC
NO. IAF cannot at present withhold both PAF and PLAAF. PLAAF will use its vintage MiG copies which are about 800 of them to overwhelm us. Their J-10, J-11 and later J-20 will be focused on Japan, South Korea and US from east. They will rely on quantity to defeat us because they are too paranoid about quality with its eastern threats.
@Those member who are saying that they have only 2 divisions there:
That's because they don't need to permanently station stuff there. Infrastructure is there, road and railways is there; if they want, they can bring in 10 divisions of PLA and hold Indian military on ground until more of MiG copies come by to these 2 divisions of PLAAF stationed in Tibet.
So what solution is there? Sign that damn MRCA contract and get the production rates of HAL to 30-50 jets per year. No less than that otherwise we as well lay down our arms and let PLA(AF) come in with ceremonial thalis. The alternative/simultaneous solution is; get those damn Akash SAMs out ASAP. Fast, many numbers and start covering the entire east. Make sure that there are 3-4 SAMs for every single jet. The focus will be defense of AP, Sikkim, Ladakh, HP and Uttarakhand; not invading Tibet. Make sure that if PLAAF jets enter, they are greeted with a rain of SAMs where there is no escape: either they get hit by SAMs or they crash on the jagged mountainous terrain trying risky maneuvers and die.
MRCA will take more time knowing HAL's slow and lack-lustre work (150 MKIs remember). So we need SAMs fast and BEL has a fairly better record. So get those damn SAMs in place and fast. Not only SAM blankets will help in forcing the PLAAF to think a 100 times before sending their jets into Indian airspace but also pose a potent risk for PLA Airborne Division to enter Indian territory. If they try, their large and bulky aircraft will be fireballs before they land.
In short: Use Chinese strength against them. Chinese rely on missiles for every form of defense. It is cheaper, effective and sends a message. Their ASBM is the latest example.
As for PAF, we need to make sure that if at all there is an invading maneuver we conduct, we must strike their forward bases in rapid successions. Get those modified Antonov transports as bomb trucks escorted by Mirage and MiG-29s. Air war with Pakistan in immediate future will prove competitive because they are inducting new jets faster than we ever have been. PAC Kamra is assembling more JFs than HAL can ever do for Tejas and MKIs.
In short victory in our air war on both sides of the border, depends not on IAF but on GOI and its many lazy and corrupt divisions.