HI Dhiraj the seats of IIT, NIT and IIIT used to get increase year by year it is now become the herarcy that the government used to increase the seats of these instutions every year. The thing is that as the number of candidates are incresing year by year it is necessary to increase the seats of these institutions. Last year Combined(IIT, NIT, IIIT) approx 1500-2000 seats had been increased in different sections of branch .

Good Luck.