Time in India

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Time in India
Time zone
UTC offset
IST UTC+05:30
Current time
09:02, 4 November 2024 IST [refresh]
Observance of DST
DST is not observed in this time zone.

India uses only one time zone (even though it spans two geographical time zones) across the whole nation and all its territories, called Indian Standard Time (IST), which equates to UTC+05:30, i.e. five and a half hours ahead of Coordinated Universal Time (UTC). India does not currently observe daylight saving time (DST or summer time).

Contents

The official time signal is given by the Time and Frequency Standards Laboratory. The IANA time zone database contains only one zone pertaining to India, namely Asia/Kolkata. The date and time notation in India shows some peculiarities.

Clock in Mysore with Kannada numerals Mysore Clocktower - clock face.jpg
Clock in Mysore with Kannada numerals

Background

History

Ancient India

The 4th century CE astronomical treatise Surya Siddhanta postulated a spherical Earth. The book described a custom of the prime meridian, or zero longitude, as passing through Avanti , the ancient name for the historic city of Ujjain, and Rohitaka, the ancient name for Rohtak ( 28°54′N76°38′E / 28.900°N 76.633°E / 28.900; 76.633 (Rohitaka (Rohtak)) ), a city near the Kurukshetra. [1]

The day used by ancient Indian astronomers began at sunrise at the prime meridian of Ujjain, [2] and was divided into smaller time units in the following manner: [3]

Time that is measurable is that which is in common use, beginning with the prāṇa (or, the time span of one breath). The pala contains six prāṇas. The ghalikā is 60 palas, and the nakṣatra ahórātra, or astronomical day, contains 60 ghalikās. A nakṣatra māsa, or astronomical month, consists of 30 days.

Taking a day to be 24 hours, the smallest time unit, prāṇa, or one respiratory cycle, equals 4 seconds, a value consistent with the normal breathing frequency of 15 breaths/min used in modern medical research. [4] The Surya Siddhanta also described a method of converting local time to the standard time of Ujjain. [5] Despite these early advances, standard time was not widely used outside astronomy. For most of India's history, ruling kingdoms kept their own local time, typically using the Hindu calendar in both lunar and solar units. [6] For example, the Jantar Mantar observatory built by Maharaja Sawai Jai Singh in Jaipur in 1733 contains large sundials, up to 27 m (90 ft) high, which were used to accurately determine the local time.

During British colonial rule

In 1802 Madras Time was set up by John Goldingham [7] and this was later used widely by the railways in India. [8] Local time zones were also set up in the important cities of Bombay and Calcutta and as Madras time was intermediate to these, it was one of the early contenders for an Indian standard time zone. [9] [10] Though British India did not officially adopt the standard time zones until 1905, when the meridian passing east of Allahabad at 82.5° E longitude was picked as the central meridian for India, corresponding to a single time zone for the country (UTC+05:30). Indian Standard Time came into force on 1 January 1906, and also applied to Sri Lanka (then Ceylon). However, Calcutta Time was officially maintained as a separate time zone until 1948 and Bombay Time until 1955. [8]

In 1925, time synchronisation began to be relayed through omnibus telephone systems and control circuits to organisations that needed to know the precise time. This continued until the 1940s, when time signals began to be broadcast using the radio by the government. [8] Briefly during World War II, clocks under Indian Standard Time were advanced by one hour, referred to as War Time. This provision lasted from 1 September 1942, to 15 October 1945. [11]

After independence

After independence in 1947, the Indian government established IST as the official time for the whole country, although Mumbai and Kolkata retained their own local time for a few more years. [8] In 2014 Assamese politicians proposed following a daylight-saving schedule that would be ahead of IST by an hour, but as of March 2020 it has not been approved by the central government. [12]

Plantations Labour Act of 1951 allows the union and state governments to define and set the local time for particular industrial areas. [13] Due to this, in regions of Assam, tea gardens follow a separate time zone, known as the Chaibagan or Bagan time ('Tea Garden Time'), which is one hour ahead of IST. [14] However, IST remains the only officially used time.

Former practices

Former timezones

Earlier time zones, no longer in use after the adoption of a standardized time zone across India, were:

Former daylight saving

India and the Indian subcontinent observed "daylight saving (DST)" during the Second World War, from 1942 to 1945. During the Sino-Indian War of 1962 and the Indo–Pakistani Wars of 1965 and 1971, daylight saving was briefly used to reduce civilian energy consumption.[ citation needed ]

Present time zone

India uses UTC+5:30, [8] referred to as Asia/Kolkata in the IANA time zone database.

See also

Related Research Articles

<span class="mw-page-title-main">Time zone</span> Area that observes a uniform standard time

A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time.

The Hindu calendar, also called Panchanga, is one of various lunisolar calendars that are traditionally used in the Indian subcontinent and Southeast Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start. Of the various regional calendars, the most studied and known Hindu calendars are the Shalivahana Shaka found in the Deccan region of Southern India and the Vikram Samvat (Bikrami) found in Nepal and the North and Central regions of India – both of which emphasize the lunar cycle. Their new year starts in spring. In regions such as Tamil Nadu and Kerala, the solar cycle is emphasized and this is called the Tamil calendar and Malayalam calendar and these have origins in the second half of the 1st millennium CE. A Hindu calendar is sometimes referred to as Panchangam (पञ्चाङ्गम्), which is also known as Panjika in Eastern India.

Indian Standard Time (IST), sometimes also called India Standard Time, is the time zone observed throughout the Republic of India, with a time offset of UTC+05:30. India does not observe daylight saving time or other seasonal adjustments. In military and aviation time, IST is designated E* ("Echo-Star"). It is indicated as Asia/Kolkata in the IANA time zone database.

<span class="mw-page-title-main">Alaska Time Zone</span> Time zone in Alaska

The Alaska Time Zone observes standard time by subtracting nine hours from Coordinated Universal Time (UTC−09:00). During daylight saving time its time offset is eight hours (UTC−08:00). The clock time in this zone is based on mean solar time at the 135th meridian west of the Greenwich Observatory.

<span class="mw-page-title-main">Time in the United States</span> Time zones in the U.S.

In the United States, time is divided into nine standard time zones covering the states, territories and other US possessions, with most of the country observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation, but no single map of those existed until the agency announced intentions to make one in September 2022. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.

<span class="mw-page-title-main">Newfoundland Time Zone</span> Time zone in Newfoundland and Labrador, Canada

The Newfoundland Time Zone (NT) is a geographic region that keeps time by subtracting 3.5 hours from Coordinated Universal Time (UTC) during standard time, resulting in UTC−03:30; or subtracting 2.5 hours during daylight saving time. The clock time in this zone is based on the mean solar time of the meridian 52 degrees and 30 arcminutes west of the Greenwich Observatory. It is observed solely in the Canadian province of Newfoundland and Labrador. The Newfoundland Time Zone is the only active time zone with a half-hour offset from UTC in the Americas.

<span class="mw-page-title-main">Time in Australia</span>

Australia uses three main time zones: Australian Eastern Standard Time, Australian Central Standard Time and Australian Western Standard Time.

<i>Surya Siddhanta</i> Sanskrit text on Indian astronomy

The Surya Siddhanta is a Sanskrit treatise in Indian astronomy dated to 4th to 5th century, in fourteen chapters. The Surya Siddhanta describes rules to calculate the motions of various planets and the moon relative to various constellations, diameters of various planets, and calculates the orbits of various astronomical bodies. The text is known from a 15th-century CE palm-leaf manuscript, and several newer manuscripts. It was composed or revised probably c. 800 CE from an earlier text also called the Surya Siddhanta. The Surya Siddhanta text is composed of verses made up of two lines, each broken into two halves, or pãds, of eight syllables each.

<i>Aryabhatiya</i> Sanskrit astronomical treatise by the 5th century Indian mathematician Aryabhata

Aryabhatiya or Aryabhatiyam, a Sanskrit astronomical treatise, is the magnum opus and only known surviving work of the 5th century Indian mathematician Aryabhata. Philosopher of astronomy Roger Billard estimates that the book was composed around 510 CE based on historical references it mentions.

Malaysian Standard Time or Malaysian Time (MYT) is the standard time used in Malaysia. It is 8 hours ahead of Coordinated Universal Time (UTC). Malaysia does not observe daylight saving time.

The UTC offset is the difference in hours and minutes between Coordinated Universal Time (UTC) and local solar time, at a particular place. This difference is expressed with respect to UTC and is generally shown in the format ±[hh]:[mm], ±[hh][mm], or ±[hh]. So if the time being described is two hours ahead of UTC, the UTC offset would be "+02:00", "+0200", or simply "+02".

Madras Time was a time zone established in 1802 by John Goldingham, the first official astronomer of the British East India Company in British India when he determined the longitude of Madras as 5 hours, 21 minutes and 14 seconds ahead of Greenwich Mean Time. It has been described as 8 minutes and 46 seconds from UTC+05:30 and 32 minutes and 6 seconds behind Calcutta Time which puts it at (UTC+05:21:14). Before India's independence, it was the closest precursor to Indian Standard Time which is derived from the location of the observatory at 82.5°E longitude in Shankargarh Allahabad in Uttar Pradesh.

Calcutta Time was one of the two official time zones established in British India in 1884. It was established during the International Meridian Conference held at Washington, D.C. in the United States. It was decided that India had two time zones: Calcutta would use the 90th meridian east and Bombay the 75th meridian east. It was determined as 5 hours, 53 minutes and 20 seconds ahead of Greenwich Mean Time (UTC+5:53:20).

Bombay Time was one of the two official time zones established in British India in 1884. The time zone was established during the International Meridian Conference held at Washington, D.C. in the United States in 1884. It was then decided that India would have two time zones, Calcutta, and Bombay. Bombay Time was set at 4 hours and 51 minutes ahead of Greenwich Mean Time (GMT).

<span class="mw-page-title-main">John Goldingham</span> British astronomer in India (1767–1849)

John Goldingham was the first official astronomer of the Madras Observatory, appointed in 1802. Goldingham was also an architect and surveyor who headed the Madras Survey School which later grew into the Guindy Engineering College and then Anna University. Born in London in 1767, Goldingham was first in the service of William Petrie at his private observatory and then hired by astronomer-sailor Michael Topping as his assistant in 1788.

<span class="mw-page-title-main">Bangladesh Standard Time</span> Time zone used in Bangladesh

Bangladesh Standard Time serves as the official time zone for Bangladesh. It operates six hours ahead of Coordinated Universal Time and is observed uniformly across the country as a national standard. In 2009, Bangladesh briefly observed daylight saving time (DST) as a measure to address an ongoing electricity crisis. However, this decision was reversed by the government in 2010.

<span class="mw-page-title-main">Bengali calendars</span> Calendar used in the Bengal region

The Bengali Calendar, is a solar calendar used in the Bengal region of the South Asia. A revised version of the calendar is the national and official calendar in Bangladesh and an earlier version of the calendar is followed in the Indian states of West Bengal, Tripura and Assam. Unlike the traditional Indian Hindu calendar which starts with the month of Choitro, the Bengali calendar starts with Boishakh because of the reforms made during the reign of the Mughal Emperor Akbar in Mughal Bengal. The first day of the Bengali year is known as Pohela Boishakh which is a public holiday in Bangladesh.

MoreSunlight or Project Moresunlight is a proposal to advance Indian Standard Time by 30 minutes. According to the proposal of MoreSunlight, the current time of India, which is +530 UTC should be advance to +600 UTC. The project is a conception of many government officers, elected representatives, members of the scientific community in India and civil society organizations and ordinary citizens.

<span class="mw-page-title-main">Astronomical basis of the Hindu calendar</span> Applied astronomy of ancient India

The Hindu calendar is based on a geocentric model of the Solar System. A geocentric model describes the Solar System as seen by an observer on the surface of the Earth.

References

  1. ↑ Schmidt, Olaf H. (1944). "The Computation of the Length of Daylight in Hindu Astronomy". Isis. 35 (3). The University of Chicago Press: 205–211. doi:10.1086/358709. JSTOR   330729. S2CID   145178197.
  2. ↑ Swerdlow, N. (January 1973). "A Lost Monument of Indian Astronomy:Das heliozentrische System in der griechischen, persischen und indischen Astronomie B. L. van der Waerden". Isis. 64 (2): 239–243. doi:10.1086/351088. S2CID   146253100.
  3. ↑ Das, Sukumar Ranjan (December 1928). "The Equation of Time in Hindu Astronomy". The American Mathematical Monthly. 35 (10): 540–543. doi:10.2307/2298168. JSTOR   2298168.
  4. ↑ Piepoli, M. 1997. "Origin of Respiratory Sinus Arrhythmia in Conscious Humans." Circulation. 95:1813–1821. Retrieved 1 December 2006.
  5. ↑ Burgess, Ebenezer (1858). "Translation of the Surya-Siddhanta, A Text-Book of Hindu Astronomy; With Notes, and an Appendix". Journal of the American Oriental Society. 6: 183–186. doi:10.2307/592174. JSTOR   592174.
  6. ↑ Tomczak, Matthias (2004-07-15). "Lecture 7: Living with the seasons—the calendar problem". Lectures on Science, civilization and society, Flinders University, Australia. Archived from the original on 2006-08-19. Retrieved 2006-12-01.
  7. ↑ William Nicholson, ed. (1809). "Eclipses of the Satellites of Jupiter, observed by John Goldingham and under his Superintendence, at Madras, in the East Indies". A Journal of Natural Philosophy, Chemistry, and the Arts. 22. London: Stratford, Crown Court and Temple Bar: 153–156.
  8. 1 2 3 4 5 "Odds and Ends". Indian Railways Fan Club. Retrieved 2006-11-25.
  9. ↑ "On Time in India". Proceedings of the Asiatic Society of Bengal. Calcutta: Asiatic Society of Bengal: 49–55. April 1899.
  10. ↑ "On the Introduction of a Standard Time for India". Proceedings of the Asiatic Society of Bengal. Calcutta: Asiatic Society of Bengal: 62–66. June 1899.
  11. ↑ "Time Zone & Clock Changes in Kolkata, West Bengal, India". www.timeanddate.com. Retrieved 2023-03-26.
  12. ↑ "India could get second time zone with Assam one hour ahead". NDTV.com. Retrieved 2023-03-26.
  13. ↑ "A matter of time". National Resource Centre for Women. Archived from the original on 19 March 2006. Retrieved 25 November 2006.
  14. ↑ Rahul Karmakar (24 September 2012). "Change clock to bagantime". Hindustan Times . Archived from the original on 6 June 2011. Retrieved 22 September 2008.
  15. ↑ "Oldham, R". cires1.colorado.edu. Retrieved 2023-03-26.
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