what is the minimum percentile in jee mains which is required to get a seat in cs of sastra with 98% boards marks
The eligibility criteria for B.Tech course in SASTRA is to pass in 10+2 or equivalent with 60% marks (Maths and Physics compulsory subjects) which I see you have cleared.
There is no criteria of minimum JEE Mains Score to secure admission.
So, if you are willing, you can apply for admission into this college for the qualification you have already got.
Hope this helps.