Depending on which grade you are and what subject you study there are some of the competitive examinations like NTSE, KVPY, Indian National Mathematical Olympiads (which is a three tier examination) etc. There can be some locally organized exams which you can participate in like the Science Quiz or Arts quiz by the universities etc organized for the school students. So you have to specifically search for it on internet specifically with your branch of study.

You can reframe a question with proper education details and we can provide you some of the competitive examination corresponding to your stream of study.

I hope this answer helps. All the very best for your future endeavors!