New Delhi, Nov. 30: Every year, there’s a mad scramble among students to make the IITs, about a 100 competing for a single seat. But at the end of admission season, some 100 seats lie vacant for want of takers.

According to admission data for the last three years, there is a trend of seats lying vacant in the elite tech institutes. Whereas 86 of 5,521 seats in 13 IITs had no takers in 2008, 113 of 6,561 seats in 15 IITs lay vacant in 2009. This year, about 90 of 9,509 seats went waste.

The IITs are of the view that most seats lying vacant are from the reserved category for physically disabled students. According to rules, three per cent seats each within the general, OBC and SC/ST categories are reserved for physically challenged students belonging to that category. These seats cannot be transferred.

“We do not get enough number of students in the physically disabled category. Since the seats cannot be allotted to other students, they remain vacant,” IIT Delhi director Surendra Prasad said.

Some seats in the SC/ST category too lie vacant. IIT Guwahati director Gautam Barua said some SC and ST students allotted seats in IITs do not turn up for admission.

“Some of them get admission in National Institutes of Technology where they get their preferred subjects. If they take admission in IITs, they may not get their preferred subjects as the competition is tough. As they do not turn up for admission, certain seats remain vacant,” he said.

A few years ago, several seats reserved for SC/ST categories used to lie vacant because not many were able to make the Joint Entrance Exam merit list. The IITs then introduced a preparatory course for students just outside the merit list, under which they would take basic courses for a year. If they qualified an exam after that, they were admitted to the institutes.

In 2008, about 3,21,653 candidates took the IIT-JEE, the number rising to 3,98,264 and 4,55,571 in 2009 and 2010 respectively. The number of seats in the IITs has increased in the last two years because of implementation of the OBC quota. Two new IITs came up at Mandi and Indore in 2009.