This Year (2018) the admission session in DU will be going to start from 15th May.

Total Number of UG Seats available – 56000
There are 77 colleges in Delhi which are affiliated with Delhi University.

In the year 2017 – 2,21,309 students applied for the 56,000 seats of UG courses in Delhi University | 4 Applications for every 1 seat in DU.
Source – 2.2 lakh aspirants vie for 56,000 Delhi University seats