IIIT Delhi was initially established as a State University on a self-sustainable model. Although the Government has provided the land and the capital the University needs a lot of funds to sustain itself in the long run. The cost increases every year due to inflation and so to maintain the balance, IIIT Delhi is left with no option but to increase its fees.
However, IIITD has provisions for fee waivers for students with weak economic backgrounds. Students are also allowed to work as TAs or interns with faculty and receive compensation given that you have an excellent academic record.
So, the hike will not stop in the near future given the fact that IIIT Delhi is still in its developing phase.