I was running through the book, Visualizing Data by Ben Fry and came across his pincode example for USA. I decided to replicate the example for India. Thus began my search for an geo-tagged dataset of indian pincodes. Sadly it does not exist. The best set of easily available data is hosted by datameet at http://pincode.datameet.org/
I ran the set through Tilemill and found large parts of India still untagged especially almost all of Maharashtra and Bihar. I asked Arun and he told me that ” there are no official public datasets available. But there is reasonably good coverage in the openstreetmap data. The simplest way to view the data is to probably use http://maperitive.net” which I will try to explore for now.
You could help by mapping your own pincode on this website. Go on, it only takes a minute.