Very debatable how superior IAF was vs PLAAF in 1980's.
IAF had ~300 Mig-21s (air superiority), ~40 Mig-23MF (air superiority), ~90 Mig-23BNs (fighter bombers), ~250 Hawker Hunters (1st gen 1940's jets), and had just received 36 Mirage-2000s, their first order of 4th gen jets in history, in 1985.
Basically ~400 3rd gen or better air superiority aircraft.
Su-30 MKI was still 15 years away.
In 1985 China had something like 2000+ J-7s and 300+ J-8s. Unlike Indian Mig-21s which were vintage Soviet that they couldn't even maintain themselves, China had fully mastered J-7 and even built the J-7E redesign in 1987.
So India in 1980's still had no chance. They didn't have a qualitative edge and had a massive quantitative disadvantage.
In the 90's, China imported S-300s (1993) and Su-27s (1992) before India imported Su-30 MKI (2002).
So there was never a time when India could beat China in the air.