You can avail the benefits of OBC only if you are going to any Delhi Government  college via qualifying National Level Examination, but if you are trying to get in the college which is under Delhi state government then the chances are less because 75% seats are reserved for Delhi home quota students and all outsiders even if they are from any reserved category then they all are seen equivalent to General category. If you are an outsider but still you have passed class 10th and 12th examination from a recognised school in Delhi then you also come under home quota and can avail the benefits of OBC category.