Dear Raunak,
While you have strong transcripts and good work experience, your GMAT is low relative to other applicants with similar education and professional experience. Consequently, you will have a bit of an obstacle to overcome to be successful at your target schools. In particular, your GMAT might not be strong enough at INSEAD where an 80% on both the quant and verbal sections is preferred. I do think NUS and Manchester are more reasonable for you; however, you will want to have a compelling application package for any school that makes a strong case for your admission. With regard to other schools, I encourage you to read our sticky on school selection for tips on identifying other programs that might be a match for you.
Good luck,
Lisa