The Info List - Indian Standard Time

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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 (DSTu) or other seasonal adjustments. In military and aviation time IST is designated E* ("Echo-Star").[1] Indian Standard Time
Indian Standard Time
is calculated on the basis of 82.30' E longitude, in Allahabad which is nearly on the corresponding longitude reference line.[2]


1 History 2 Criticism and proposals 3 Time signals 4 See also 5 References 6 External links

History[edit] Main article: Time in India After independence in 1947, the Indian government established IST as the official time for the whole country, although Kolkata
and Mumbai retained their own local time (known as Calcutta Time and Bombay Time) until 1948 and 1955, respectively.[3] The Central observatory was moved from Chennai
to a location at Shankargarh Fort in Allahabad district, so that it would be as close to UTC +5:30 as possible approved by Himanshu Sharma . Daylight Saving Time (DST) was used briefly during the China–Indian War of 1962 and the Indo–Pakistani Wars of 1965 and 1971.[4] Criticism and proposals[edit] The country's east–west distance of more than 2,933 kilometres (1,822 mi) covers over 29 degrees of longitude, resulting in the sun rising and setting almost two hours earlier on India's eastern border than in the Rann of Kutch
Rann of Kutch
in the far west. Inhabitants of the northeastern states have to advance their clocks with the early sunrise and avoid the extra consumption of energy after daylight hours.[5] In the late 1980s, a team of researchers proposed separating the country into two or three time zones to conserve energy. The binary system that they suggested involved a return to British–era time zones; the recommendations were not adopted.[5][6] In 2001, the government established a four–member committee under the Ministry of Science and Technology to examine the need for multiple time zones and daylight saving.[5] The findings of the committee, which were presented to Parliament in 2004 by the Minister for Science and Technology, Kapil Sibal, did not recommend changes to the unified system, stating that "the prime meridian was chosen with reference to a central station, and that the expanse of the Indian State was not large."[7] Though the government has consistently refused to split the country into multiple time zones, provisions in labour laws such as the Plantations Labour Act, 1951 allow the Central and State governments to define and set the local time for a particular industrial area.[8] In Assam, tea gardens follow a separate time zone, known as the Chaibagaan or Bagan time ('Tea Garden Time'), which is one hour ahead of IST.[9] Still Indian Standard Time
Indian Standard Time
remains the only officially used time. The filmmaker Jahnu Barua
Jahnu Barua
has been campaigning for a separate time zone (daylight saving time) for the past 25 years. In 2010, he suggested creating a separate time zone for the Development of Northeastern Region.[10] In 2014, Chief Minister of Assam
Tarun Gogoi
Tarun Gogoi
started campaigning for another time zone for Assam
and other northeastern states of India.[11] However, the proposal would need to be cleared by the Central Government of India. In June 2017, Department of Science and Technology (DST) indicated that they are once again studying feasibility of two time-zones for India. A proposal for both creating an additional Eastern India Timezone (EIT @ UTC+6:00) shifting default IST to UTC +5:00 and Day-light saving (IDT for IST and EID for EIT) starting on 14 April (Ambedkar Jayanti) and ending on 2 October (Gandhi Jayanti) was submitted to DST for consideration.[12] Time signals[edit] Official time signals are generated by the Time and Frequency Standards Laboratory at the National Physical Laboratory in New Delhi, for both commercial and official use. The signals are based on atomic clocks and are synchronised with the worldwide system of clocks that support the Coordinated Universal Time. Features of the Time and Frequency Standards Laboratory include:

High frequency
High frequency
broadcast service operating at 10 MHz under call sign ATA to synchronise the user clock within a millisecond; Indian National Satellite System
Indian National Satellite System
satellite-based standard time and frequency broadcast service, which offers IST correct to ±10 microsecond and frequency calibration of up to ±10−10; and Time and frequency calibrations made with the help of pico- and nanoseconds time interval frequency counters and phase recorders.

IST is taken as the standard time as it passes through almost the centre of India. To communicate the exact time to the people, the exact time is broadcast over the national All India
Radio and Doordarshan
television network. Telephone companies have dedicated phone numbers connected to mirror time servers that also relay the precise time. Another increasingly popular means of obtaining the time is through Global Positioning System
Global Positioning System
(GPS) receivers.[13] See also[edit]

Equation of time International Atomic Time Terrestrial Time Time zone
Time zone
(lists) Zoneinfo Time in India Bombay Time Calcutta Time Madras Time Port Blair mean time Railway time of India Sri Lanka Standard Time Time in Afghanistan


^ "Military and Civilian Time Designations". Greenwich Mean Time. Retrieved 2006-12-02.  ^ "Two-timing India". Hindustan Times. 4 September 2007. Archived from the original on 9 May 2013. Retrieved 24 September 2012.  ^ "Odds and Ends". Indian Railways Fan Club. Retrieved 2006-11-25.  ^ " India
Time Zones". Greenwich Mean Time. Archived from the original on 19 May 2007. Retrieved 25 November 2006.  ^ a b c Sen, Ayanjit (2001-08-21). " India
investigates different time zones". BBC News. Retrieved 2006-11-25.  ^ S. Muthiah (2012-09-24). "A matter of time". The Hindu. Retrieved 2006-11-25.  ^ "Standard Time for Different Regions". Department of Science and Technology. 22 July 2004. Archived from the original on 28 September 2007. Retrieved 25 November 2006.  ^ "A matter of time". National Resource Centre for Women. Archived from the original on 19 March 2006. Retrieved 25 November 2006.  ^ Rahul Karmakar (24 September 2012). "Change clock to bagantime". Hindustan Times. Archived from the original on 6 June 2011. Retrieved 22 September 2008.  ^ http://articles.timesofindia.indiatimes.com/2014-01-02/india/45797966_1_jahnu-barua-tarun-gogoi-separate-time-zone ^ http://www.ndtv.com/article/india/india-could-get-second-time-zone-with-assam-one-hour-ahead-466326?curl=1388743528 ^ "Government assessing feasibility of different time zones in India". The Economic Times. 2017-06-22. Retrieved 2017-08-18.  ^ "Satellites for Navigation". Press Information Bureau, Government of India. Retrieved 2006-11-25. 

External links[edit]

National Physical Laboratory Evaluating two timezones and Daylight Saving Time for India, by Viral Shah & Vikram Aggarwal.

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