The full form of “IST” is Indian Standard Time. Indian Standard Time (IST) is the time observed throughout India, with a time offset of UTC+05:30. India does not observe daylight saving time, so IST is the same all year.
IST is calculated based on the 82.5 degrees East longitude, which passes through Allahabad in Uttar Pradesh, India. This is the reference point for calculating the standard time for the entire country. The time at this reference point is called the “meantime” and all other times in India are calculated based on the difference from this reference point.
The Indian government established IST in the year 1884, as a standard time for the entire country. Prior to this, each region in India had its own local time, which created confusion and difficulties in communication and transportation. The establishment of IST helped to standardize time across the country and improve efficiency in transportation and communication.
IST is also used as a time standard in several countries in the Indian subcontinent, including Bangladesh, Bhutan, Maldives, Nepal, Pakistan and Sri Lanka, as well as in the British Indian Ocean Territory.
In addition to IST, India also uses other time zones for certain regions and territories. For example, the Andaman and Nicobar Islands, which are located in the Bay of Bengal, use the Andaman and Nicobar Islands Time (ANIT), which is UTC+06:00. The Lakshadweep Islands, which are located in the Arabian Sea, use the Lakshadweep Time (LKT), which is UTC+05:30.
In conclusion, IST stands for Indian Standard Time, which is the time observed throughout India, with a time offset of UTC+05:30. It is calculated based on the 82.5 degrees East longitude, which passes through Allahabad in Uttar Pradesh, India. Indian government established IST in the year 1884, as a standard time for the entire country. It is also used as a time standard in several countries in the Indian subcontinent. India also uses other time zones for certain regions and territories.