A typical hostel room at BIT Mesra is a 10*10 space. It has single occupancy and contains a bed, a chair, a table, and a few racks to keep your belongings. Each room has proper ventilation. The windows face the open grounds which grants easy access to mosquitoes and flies into the rooms. Each room has a tubelight and a fan. Some hostel rooms are comparatively new, while the others are a bit old. However, the rooms are pretty decent and have decent space for a single occupant.
My brother lived in hostel 10, 7 and 5 during his first, second and third year, respectively. The rooms in these were new and pretty decent. During his final year, he stayed at hostel 3 and his room was decent but very old. However, in the same hostel, his friend got a room which looked new.
The rooms at BIT Mesra are good enough and you will find them livable.