Postal Index Number

The PIN system was introduced on 15 August 1972 by Shriram Bhikaji Velankar, an additional secretary in the Government of India's Ministry of Communications.

[1][2][3] 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.

The fourth digit represents the route on which a delivery office is located in the sorting district.

Special cases where mail needs to be sent to locations overseas is handled in an ad hoc manner.

Branch offices (BOs) are located in rural areas and have limited postal services.

An example of a Postal Index Number from Ujjain in Madhya Pradesh . 4 indicates the West postal zone , 5 indicates a postal sub-zone in Madhya Pradesh , 6 indicates the Ujjain sorting district , 0 indicates the Ujjain core area service route , 01 indicates the Ujjain Head Office as the delivery office.
2-digit postcode areas in India (defined through the first two PIN digits)
A post box with its PIN marked on it