Hey,
The criteria decided by the respective college for their admission is decided by the college itself and is to be met if you want to take admission in that college. The DELHI UNIVERSITY usually deduct marks in counting the best of four percentage if the necessary subjects are not included in calculating the percentage.
There might be that the both the courses are different in DU. Hence they are doing it. You can talk to them about it but the decision taken by them will be final.
Hope that helps.
Thank you.
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