Hi Subham, the minimum percentage eligibility criteria set by the clllege is around 40-45% in 12th exam, but the competition is very very high. You need to score at a very high percentage above 97-98% if you have to stand a chance for getting in a seat at DU. You can refer to this link below, which gives differemt details about DU and eligibility marks, 

https://university.careers360.com/articles/du-eligibility-criteria