Dear student,

There is no such hard and fast rule about the dressing code in IIT. You may find many students wearing a full pant or shorts with slippers or sandles.
Just beware in first and second year. Because in first and second year you will be checked and you must have to wear what your instructor say and it cam be shoes too.
After from third year, no one will question your dress code in any way. This is a fact in every iits.