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Postal Index Numbers: How Do India's Pin Codes Work?

PIN stands for Postal Index Number Codes, which are 6-digit codes used by the Indian Post as part of the postal office numbering system, with each of the 6 digits having a particular meaning. It is also known as zip code or area postal code.

On 15 August 1972, Shriram Bhikaji Velankar, an additional secretary at the Union Ministry of Communications, introduced the PIN system.

The method was implemented to streamline the hand sorting and distribution of mail by avoiding confusion caused by inaccurate addresses, similar location names, and various languages spoken by the people.

It also helped with organising the different ways in which the name of a place

could be spelt.


The first digit of a PIN represents the zone, the second represents the sub-zone, and the third, in conjunction with the first two, represents the sorting district within that zone. Within the sorting district, the final three numbers are given to particular post offices.


In India, there are nine postal zones, eight regional zones and one functional zone (for the Indian Army). The first digit of a PIN denotes the zone and is distributed as follows throughout the 9 zones:


1- North - Delhi, Haryana, Punjab, Himachal Pradesh, Jammu & Kashmir, Ladakh, Chandigarh

2 - North - Uttar Pradesh, Uttarakhand

3 - West - Rajasthan, Gujrat, Daman & Diu, Dadra and Nagar Haveli

4 - West - Maharashtra, Madhya Pradesh, Chattisgarh

5 - South - Telangana, Andhra Pradesh, Karnataka

6 - South - Tamil Nadu, Kerala, Puducherry, Lakshadweep

7 - East - West Bengal, Odisha, Arunachal Pradesh, Mizoram,Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Assam, Sikkim, Andaman & Nicobar Island

8 - East - Bihar, Jharkand

9 - APS - Army Postal Service, Field Post Office


These zones are further divided into sub-regions, which are often the states or Union territories.


The third number of a PIN, when paired with the first two digits, denotes a specific geographical region called a sorting district, which is headquartered at the main post office of the major city in the region and is referred to as the sorting office. Depending on the volume of mail processed, a state may have many sorting districts.


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

The digit is 0 for office that are located in the core area of the sorting district.


The final two digits indicate the delivery office within the sorting district, beginning with 01 for the General Post Office (GPO) or head office (HO). The numbering of delivery offices is done in chronological order, with higher numbers issued to delivery offices that are more recent.

If a delivery office receives an excessive amount of mail, a new delivery office is formed and the next available PIN is allocated. Thus, two adjacent delivery offices will share just the first four digits of their ZIP codes.


Each PIN is associated with a single sorting facility that processes mail for distribution to one or more branch locations within its purview. Typically found in densely populated locations, the delivery office might be a General Post Office (GPO), a Head Office (HO), or a Sub Office (SO).

Upon arrival at the delivery office, mail is processed and then sent to the appropriate destination, whether it be another delivery office for a different PIN or a relevant sub-office or branch office for the same PIN. Postal service is more limited at branch offices (BOs) because they are typically found in rural villages.


Which country invented PIN code?

The first modern postal codes were introduced in 1932 in Ukraine, which was then under the Soviet Union, only to be abandoned in 1939. It was slowly adopted in the United Kingdom under the name of “postcode” and in the US, as the “zip code”.

Which Cities got Thier Pincodes at first in India ?

On April 1, 1774, India got its three first postal circles: Bengal, Bombay and Madras. As the date suggests, this was one of first things that the British did once they began to colonise the country.

While Bengal catered to the whole of the eastern and northern regions of British Empire, Madras handled the southern region and Bombay, the rest.

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