MapmyIndia's detailed online maps
Recent updates include house number level precision.
MapmyIndia seems to be heading in the right direction. Their free to use web maps (link) have just been updated to house number level precision in 18 cities.
You can simply zoom to the last level on MapmyIndia Maps and see exact locations on the map for residential house numbers, commercial building addresses and names, apartment complexes, businesses and points of interest in those 18 major cities.
Besides house numbers, you can also see building footprints (which shows the built-up area) in Delhi and Mumbai. Just zoom into ‘Greater Kailash 2, New Delhi’ and see footprints and buildings along with their associated house numbers. In the current online release house numbers are viewable on the map; search for house numbers is slated for future release.
It's a great utility to use to locate points of interest and other utilities like banks, ATMs, car service centers and even post boxes in any area. Check it out right here.