Hey aspirant,

There are plenty of Science project competitions in which you can take part after your board exams, which are :-

ISRO Cyberspace Competition

BrainX National Maths Contest

Aviva Young Scholar Nat Geo Junior Hunt

National Talent Search Examination or NTSE

National Space Society (NSS) Space Settlement Contest 2020

IRIS National Science Fair

National level Olympiads ( NSS, NCO. , etc. )

Hope this helps,

All the best!