Hey, 

for most of the courses the admission in DU is on the basis of performance in class 12th i.e. merit based. But for some courses like bba, bms, etc an entrance exam is held called DUJAT. So check whether admission in your course is on the basis of entrance exam or merit.

Hello,
DU doesn't conduct entrance exams for 2019-20 as they still haven't decided to do so, but they consider 12th percentage for now!! There maybe changes in further future regarding entrance exams for all courses.
For more details, you can check the link below.

https://www.google.com/amp/s/www.thehindu.com/news/cities/Delhi/no-plans-to-conduct-entrance-test-for-all-du-courses-in-2019/article25793196.ece/amp/

And regarding the official details and admissions
Check the link below

http://www.du.ac.in/du/index.php?page=ug-admission

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