Yes, as the rooms were designed and built for a single person per room, thus adjusting two people will make it a little congested. But it would not be a problem as the students will be provided with double-decker beds.
There will be proper space for two tables and chairs. The rooms in the hostel have proper ventilation.
If the student wants to sleep on the floor, they can remove the double-decker beds from their room. They will be provided with two cupboards in one room, each for a student. The students can put all their belongings there.
In comparison with some other institutions such as IIT BHU, where three of the beds are arranged in U-shaped with a table in the center of the room, the condition of IIIT Guwahati is much better.
Even after knowing all these facts, if there is any doubt about the room then you should visit the campus or talk with the current students over there and try to know about any ongoing issue about the same.