You need to score 50% aggregate marks in 10th (with Mathematics, Science and English) or equivalent. For a candidate, who has not studied English as a subject, the condition of English may be waived off provided the candidate in his qualifying exam has studied in English medium or an equivalent subject.
No, since MBA is a postgraduate degree, you’ll have to first complete your UG before opting for it. You’ll have to complete your undergraduate degree with at least 50-55% marks. Top colleges like IITs and IIMs mostly require at least 60% or more. You can study any kind of UG degree, and then try for an MBA.