<P> A Postal Index Number or PIN or PIN code is a code in the post office numbering or post code system used by India Post, the Indian postal administration . The code is six digits long . </P> <P> The PIN Code system was introduced on 15 August 1972 by Shriram Bhikaji Velankar, an additional secretary in the Union Ministry of Communications . The system was introduced to simplify the manual sorting and delivery of mail by eliminating confusion over incorrect addresses, similar place names and different languages used by the public . </P> <P> There are nine PIN zones in India, including eight regional zones and one functional zone (for the Indian Army). The first digit of the PIN code indicates the region . The second digit indicates the sub-region, and the third digit indicates the sorting district within the region . The final three digits are assigned to individual post offices . </P>

When was pin code system introduced in india