INDIAN POSTAL INDEX NUMBERING SYSTEM has 6 digits.India has There are 8 PIN regions. The first digit indicates one of the regions. The first 2 digits together indicate the sub region or one of the postal circles. The first 3 digits together indicate a sorting / revenue district. The last 3 digits refer to the delivery Post Office.
The PIN code of post offices in the state of Maharashtra, thus, starts with a number from 40 to 44.
Example:Bharat Nagar PO in Mumbai is 400007 and Pune City Head Office is 411002.
More details in : http://www.indiapost.gov.in/Netscape/Pincode.html