Yes, you can definitely apply to GIBS Bangalore after your B.Com from Delhi University with 81%. That's a really good score!
GIBS doesn't offer full “direct admission” just based on marks—you'll also need to have appeared for an entrance exam like CAT, MAT, CMAT, XAT, ATMA, GMAT, or any State-level CET. Even an average score is okay—they mainly want to see that you've taken one of these tests.
After that, they have a simple selection process where you'll write an SOP (Statement of Purpose), and then go through a Group Discussion and Personal Interview. If you're confident and serious about building your career, GIBS is very suppo