It’s how India’s PIN Codes work

What are PIN codes?

PIN or Postal Index Number codes, are 6-digit codes which are part of the postal office numbering system used by India Post. These are also known as Zip codes or area codes and each of the six digits has a particular meaning.

Brief history

The PIN Code system was introduced in India by Shriram Bhikaji Velankar, who had served as an additional secretary in the Union ministry of communications. Its implementation began from August 15, 1972, with the objective of simplifying the sorting of mails, speeding up mail transmission and delivery.

The need for such a system was realised due to the confusion resulting from the duplication of names of various places across the country, the use of multiple languages to write addresses, and different ways in which the name of a place could be spelt. For example, in Tamil Nadu, names like Mettur and Aathur are very common. PIN codes help postmen deliver the letters to right people.

FIRST DIGIT: Postal zone SECOND DIGIT: Sub-zone/ state or Union territory

The first digit indicates postal zones which range from 1 to 9. There are 9 postal zones in India. The postal zones are further divided into sub-regions, which are denoted by the second digit. The sub-regions are often the states or Union territories. It’s indicated as:

THIRD DIGIT: Sorting district

Combined with first two digits, the third one points to specific geographical regions (except in the case of the functional zone for the Army). This geographical region is known as a sorting district, which is headquartered at the main post office of the largest city in the region and is called the sorting office.

 

FOURTH DIGIT: Service routes

The fourth digit represents the route on which a delivery post office is located within the sorting district. This digit is 0 for offices which are located in the core area of the sorting district. The third and fourth digit combined zoom in on the mail-sorting district within each state.

LAST TWO DIGITS: Individual post 0ffice

The fifth and sixth digits together identify the specific post-office whose jurisdiction the address falls under. Starting from 01, which indicates the General Post Office (GPO) or head office (HO) in the area, this numbering is done chronologically and higher numbers are assigned to newer delivery offices. If the volume of mail handled at a delivery office is very large, a new delivery office is created and the next available PIN is assigned to that office.

As a result, any two delivery offices situated next to each other in an area will have the first four digits in common.