The question is itself a big question. It always depends the person taking your interview and everyone has their own style of asking questions.
It's best to check HDFC website in depth along with their historic and upcoming achievements, such as...
What exactly HDFC do?
What role you can play in keeping the HDFC as a brand?
What do you want to do the job in the Banking sector?
What things do you know about Banking? etc
Be confident and honest in giving your answer. There are many community websites which share details about the same - Glassdoor, Jobbuzz etc.