Time in India

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Time zones of South Asia (numbers are hours ahead of UTC) IST-CIA-TZ.png
Time zones of South Asia (numbers are hours ahead of UTC)
Time in India
Time zone
UTC offset
IST UTC+05:30
Current time
23:16, 28 September 2022 IST [refresh]
Observance of DST
DST is not observed in this time zone.

The Republic of India uses only one time zone (even though it spans across 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).


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



Ancient India

The 4th century CE astronomical treatise Surya Siddhanta postulated a spherical earth. The book described the thousands years old customs 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 90 ft (27 m) 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 September 1, 1942, to October 15, 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]

Former practices

Former timezones

Older time zones, not in use any more since introduction of standardised same 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.

A yuga, in Hinduism, is generally used to indicate an age of time.

The Hindu calendar, Panchanga or Panjika 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(Based on the King Shalivahana, also the Indian national calendar) 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 (पञ्चाङ्ग), which is known also known as Panjika in Eastern India.

Indian Standard Time (IST), sometimes also called India Standard Time, is the time zone observed throughout 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.

Nakshatra is the term for lunar mansion in Hindu astrology and Indian Astronomy. A nakshatra is one of 27 sectors along the ecliptic. Their names are related to a prominent star or asterisms in or near the respective sectors.

<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.

The Tamil calendar is a sidereal Hindu calendar used by the Tamil people of the Indian subcontinent. It is also used in Puducherry, and by the Tamil population in Sri Lanka, Malaysia, Singapore, and Mauritius. Tamil Nadu farmers greatly refer to this. It is used today for cultural, religious and agricultural events, with the Gregorian calendar largely used for official purposes both within and outside India. The Tamil calendar is based on the classical Hindu solar calendar also used in Assam, West Bengal, Kerala, Manipur, Nepal, Odisha, Rajasthan and Punjab

Utpala or Bhaṭṭotpala is the name of a 10th-century Indian commentator of Vārāha Mihira's Brihat Samhitā. Brihat Samhitā is a Samhitā text of Jyotiṣa. Samhitā is one of three branches of Jyotiṣa.

<span class="mw-page-title-main">Shukra</span> Deity of the planet Venus

Shukra is a Sanskrit word that means "clear" or "bright". It also has other meanings, such as the name of an ancient lineage of sages who counselled Asuras in Vedic history. In medieval mythology and Hindu astrology, the term refers to the planet Venus, one of the Navagrahas.

Astronomy has long history in Indian subcontinent stretching from pre-historic to modern times. Some of the earliest roots of Indian astronomy can be dated to the period of Indus Valley civilisation or earlier. Astronomy later developed as a discipline of Vedanga, or one of the "auxiliary disciplines" associated with the study of the Vedas, dating 1500 BCE or older. The oldest known text is the Vedanga Jyotisha, dated to 1400–1200 BCE.

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

The Surya Siddhanta is a Sanskrit treatise in Indian astronomy from the late 4th-century or early 5th-century CE, 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 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.

Madras Time was a time zone established in 1802 by John Goldingham, the first official astronomer of the British East India Company in 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 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>

John Goldingham FRS 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 (BST) is the time zone of Bangladesh. It is offset six hours ahead of Coordinated Universal Time, and observed as a national standard throughout the country. Bangladesh briefly observed daylight saving time (DST) in 2009 to cope with the ongoing electricity crisis, but in 2010 the decision was cancelled by the government of Bangladesh.

<span class="mw-page-title-main">Bengali calendars</span>

The Bengali Calendar or Bangla Calendar, colloquially, is a solar calendar used in the Bengal region of the Indian subcontinent. 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. The New Year in the Bengali calendar is known as Pohela Boishakh.

<span class="mw-page-title-main">Time in the Danish Realm</span> Time zones of Denmark and its dependencies

Denmark, including the dependencies Faroe Islands and Greenland, uses six time zones.

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.


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  11. "Time Zone & Clock Changes in Kolkata, West Bengal, India".
  12. India may get its second time zone if Assam turns its clock ahead by an hour
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