AIR INDIA 403 is a domestic flight operated from the domestic terminal of t3 at delhi. you will get off the aircraft at delhi and WILL HAVE TO do your immigration and customs at delhi airport itself. i am not very sure how your bags are handled at delhi airport in such a situation but i am assuming you will have to collect them, clear customs and then check them in again at the transfer desk. hopefully there will be an air india SATS guy standing the moment you get off the aircraft at delhi and he should be able to guide you. its winter and the flight from chicago should come in early giving you 15-20 min addtional time hopefully.

ai 403 is also being operated by a 787 these days so you should be lucky enough to be sitting in one. after rechecking in your bags, you will pass security and board the aircraft for bangalore.

if by chance your flight from chicago is late, you should be accomodated on to a later flight of air india to bangalore without any issues. however, if there are a lot of you connecting, they may even keep the flight waiting.