Hello,

Admission in colleges of University of delhi are based on cut off list which is prepared on basis of marks obatined by students in there 12th class.

For economics honours or political science honours you son needs to score above 90% because he has pursued 12th with pcm and in du when there is change in stream from science to arts or commerce to arts than deduction of 5% from percentage of best four subjects gets deducted.

All the best.