First, you'll undergo the HR Interview. There you'll be asked questions about your internships and college achievements. (Based on my experience, this is just a typical interview where you have to pitch your template statements about your experience.)
After passing the HR interview, you'll advance to the Departmental Interview which consists of more than 3 interviewers specializing in different fields of your interest. For Civil department, they'll grade you based on how you present yourself while speaking in English. They do this by asking questions that are answerable by storytelling. Technical questions are also asked, but they are nothing of a worry so far as long as the design concepts taught in college are still fresh on you.
After passing the Departmental Interview, you'll advance to the final interview. This is a very short interview. 5 mins would be too long for this based on my experience, so better answer the questions straightforwadly.