Hello Akash,

The deductions in the percentage happens when you change your stream for example if you are from science and you want to get admission in commerce stream in the graduation. The deduction is totally dependent on which college you choose but the average varies from 2.5% to 5%. 

If you can tell me the colleges in which you are interested than I can tell you the exact figure. But there is a alternate option also and i.e. you can visit the official website and download the notification. The link for offical website is- www.du.ac.in

I hope I was able to answer your query and hope you do well in future.