IST Full Form

IST full form is  Indian Standard Time. It is the zone of time which is measured or observed all over India. IST is 5 hours and 30 minutes ahead of the Green Meridian Time. The Indian Standard Time is at present maintained and managed by the authority known as the Council of Scientific and Industrial Research - National Physical Laboratory (CSIR-NPL) with assistance from the Allahabad Observatory. Do you know about the origin and how is IST calculated? Read on to gain an insight on the various details of IST.

What is IST Full Form?

IST full form is the Indian Standard Time which defines the standard time of a place or a country that is established by a law of the general usage as the civil time. Daylight saving time or other seasonal adjustments are not observed in India.The time is observed throughout India and the entire region of Sri Lanka using the time offset of UTC+05.30. The longitude of 82° E meridian can be called the standard time of the entire country.  Indian standard time has passed through the region of Mirzapur, Uttar Pradesh. India needed multiple standard times as there were time differences of approximately 2 hours between the westernmost and easternmost areas of India.  There has been a single time zone in India since 1947. After independence, the union government declared the Indian standard time as the official time for India though India opted to observe daylight saving time.

History of IST

It was after the independence of India in 1947 that the Union Government set up IST as the time zone officially for complete India. Up until 1948 and 1955, Kolkata and Bombay had their own local time zones, respectively called the Calcutta time and Bombay Time. Moreover, the central observatory was then shifted from Chennai to some location in Uttar Pradesh, so that it would be closer to the + 5:30. During the India China war of 1962 and the India Pakistan war of 1965 and 1971, the Daylight Saving Time (DST) was in potential use. During the colonial era, the meridian passing east of Allahabad was considered as the British Indian standard time zone. This was further declared to be the Indian Standard Time zone in 1947.

Origin of the Standard Time

As a concept of time measurement, it was introduced when the local times started becoming impediment in the way of administration, specifically railway times, in the nineteenth century. The presence of multiple local times didn't let the decision makers create a stable timetable due to the variation in time zones. This issue was more prominent and existing in bigger regions and countries such as Canada and the United State of America. Here, the local train route used to cover long distances and very often passed through locations that differed by many hours, as under the notion of local time. In the 1870s, Sir Sandford Fleming, introduced the world to the idea of worldwide and uniform standard time.

How is IST Calculated?

82.5° E longitude is considered as the reference longitude for the Indian Standard Time. The clock tower in Mirzapur is the exact reference where longitude is located. Nowadays, various countries choose to have multiple standard time zones, as the concept of standard time has been primarily introduced for administrative convenience. Countries like the USA, Russia, France, Canada and many others have more than one standard time.

What is the Need for a Standard Time Zone?

The standard time is set in accordance with the prevailing law and administration of a country or a region specifically. It is to fulfill and synchronize the various different time zones of that country or region to a standard time. 82°5 E Longitude passing through Naini near Allahabad was chosen as the standard meridian for the whole dominion of India because there is more than a one-hour time difference in western India and eastern India respectively. The easternmost point is about (+5:00 ahead of GMT) and the westernmost point is about (+6:00 ahead of GMT). So as to standardize and regulate the time of the whole country the mid-point is taken from the longitude passing through central India.

Difference Between IST and GMT

IST full form is Indian Standard Time while GMT full form is Greenwich Mean Time. To use as a reference time, GMT is used as it is the time at the Prime Meridian (which is considered as the line of longitude which is defined as 0 degrees and runs from the North Pole to South Pole. Whereas, IST is considered as the time in the Indian Subcontinent which is 5 hours and 30 minutes ahead of GMT.

Similarly, if it is 12:00 GMT, it would be 5:30 PM in IST. Generally, IST and GMT are used as the standard time in different regions and are widely used for different purposes. But, GMT is being more commonly used as a reference time. IST is the standard time in India and the surrounding countries. However, the basic difference between IST and GMT is based on various factors such as history, countries that follow that specific time zone, and how both of the time are calculated.

GMT full form is Greenwich Mean Time which was established in 1675. The Shepherd Gate Clock showcases GMT time at the Royal Observatory in Greenwich, London. As per location, when the sun is at its highest point above the Prime Meridian, it is noon at Greenwich. It is the reference point for every time zone in the world. Some of the countries are the UK, Iceland, Greenland and Ghana. GMT Time or Greenwich Mean Time in India is calculated on Earth’s 0 degree longitude which generally passes through Old Royal Observatory nearby London. Currently, GMT is known as the Universal Coordinated Time (UTC). In India, the IST is used as the standard unit of time measurement and abroad, GMT is used as the measurement of time. The countries that use IST are used in India and Sri Lanka. GMT is used in the UK and in other commonwealth nations such as Australia, New Zealand and other countries of the Eastern Hemisphere.

What are the Advantages of Indian Standard Time?

The adoption of the concept of a universal standard time was to serve multiple purposes. The following mentioned are some of the significant advantages of standard time:

1. IST promotes administrative uniformity. It helps in deciding the timetables and time-bound orders.
2. IST promotes coordination of many economic activities. Helps in coordinating economic exchanges and activities.
3. Creates a sense of belongingness. An IST engages the sense of harmony and togetherness within the population.
4. IST promotes national integration. The sense of belongingness created helps in the advancement of national integration.
5. Helps in fixing DST- About 40 percent of the world's countries, including the United States, use the ‘standard time’ as a reference to set Daylight Saving Time during the summer months.

Disadvantages of Standard Time

Although the concept of standard time is the predominant time concept followed by the world today, it also consists of certain disadvantages. Following are the certain disadvantages of IST:

1. Lack of synchronization of clocks with the earth's rotation- Standardization of time according to geographical borders often leads to deviation of the clock-time from the earth's rotation. Therefore, the real clock-time is not always followed.
2. IST ignores the movement of the sun- The local time of the central meridian is considered as standard time often ignores the position of the sun.
3. Wastage of energy resources- As the standard time is often derived from the process of the movement of the sun and the earth, a considerable amount of energy resources encounter wastage.
4. A hindrance for astronomers- Astronomers' work is not dependable under legally fixed clock- time. Rather their job requires the precise time of a particular location to explain their observations which is quite not possible.
5. IST has less effect on people's daily activities- Even though the standard time of a country brings about uniformity in its administrative activities, its impact on ordinary people's day-to-day activities is not that impactful.