I have below 50% in 12th and my graduation score is 70%. Am I eligible for MBA colleges?

Yes, you can easily do an MBA even if your class 12th mark is less than 50%. If you can get above 95 percentile in CAT you can surely get into one of the top B-schools in the country. Many b-schools shortlist based on the CAT score.

Yes you are eligible for MBA, you have to give some entrance exams like CAT NMAT Then after this you can take admission in MBA, some of the top most colleges in India are IIM university NMIMS University DPU university Manipal university Amity University LPU university.