Why college fees is increasing following a positive ramp function?

Every year a new Engineering batch starts, I get a shock when I hear, the fees of my college is increased by at least 15-20K per year. In fact, this is the story of all Engineering colleges. When I try to analyze the condition, I get no strong reason for the hike in fees. Even if there is an increase in cost of living, hiking the fees by 15-20K per student is not at all justified. I want to know, whether any government regulation is set up to take care of the threshold value?
Also, can anyone share their views/thoughts why the fees is increasing? Is it justified?