A PIN code, or Postal Index Number code, is a numerical code used by postal services to identify specific geographic regions and locations for efficient sorting and delivery of mail. In India, the term "PIN code" is commonly used, while in many other countries, it's referred to as a postal code or ZIP code.

The PIN code system was introduced in India by the Indian Postal Service on August 15, 1972, to simplify and streamline the process of mail delivery. A typical PIN code is a six-digit number that helps postal workers and automated sorting systems route mail accurately to the intended destination.

The six-digit PIN code is structured as follows:

  • The first digit represents the region of the country.
  • The second digit narrows down the geographical area within the region.
  • The third digit specifies the specific district within the area.
  • The last three digits help identify the exact post office within the district.

For example, in the PIN code 110001:

  • 1 indicates Northern region.
  • 10 narrows it down to a particular zone within the Northern region.
  • 001 represents the specific post office in that zone.

PIN codes are essential for accurate and efficient mail delivery and are often used in various online forms, applications, and databases to help identify and locate addresses.