Hello geeteshaiyer, thanks for your question.
What is the US equivalent of your undergraduate GPA?
In terms of GMAT, your 640 is below average, especially since you come from an overrepresented demographic in the MBA applicant pool.
Your competitiveness will come down to the quality of your leadership experience both in and out of the office. Can you draw upon “moments” when you truly led: influenced individuals and organizations, drove results, took initiative?
In terms of extracurricular activities, what you’ve done more recently has more weight than what you did in university/school. Your NGO work and potentially your singing experience could be interesting things to write about.
It’s hard to make an exact pronouncement on your competitiveness at those programs with limited information. If your GMAT is above the mean or at least within the middle 80% range, you would have a shot, depending on how compelling your essays are.
You haven’t mentioned your post-MBA goals at all. I encourage you to paint a picture that cohesively ties together your past, present, and future and demonstrate to the admissions committees that your desired career path necessitates an MBA.
Best of luck,
Brian