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Indian Standard Time
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.
The Indian Standard Time was adopted on 1 January 1906 during the British era with the phasing out of its precursor Madras Time (Railway Time), and after Independence in 1947, the Union 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. 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+05:30 as possible.
Daylight Saving Time (DST) was used briefly during the China–India War of 1962 and the Indo-Pakistani Wars of 1965 and 1971.
Indian Standard Time is calculated from the reference longitude of IST at 82°30'E passing near Vindhyachal of Mirzapur district in Uttar Pradesh. In 1905, the meridian passing east of Allahabad was declared as a standard time zone for British India and was declared as IST in 1947 for the Dominion of India. This longitude of 82°30'E was chosen as the standard meridian for the whole country as it is located centrally between western India (local time UTC +05:00) and northeastern India (local time UTC +06:00). Currently, the National Physical Laboratory of India maintains the Indian Standard Time with the help of the Allahabad Observatory.
The country's east–west distance of more than 2,933 kilometres (1,822 mi) covers over 29° of longitude, resulting in the sun rising and setting almost two hours earlier on India's eastern border than in the Rann of Kutch in the far west. Inhabitants of the northeastern states have to advance their clocks with the early sunrise to avoid the extra consumption of energy after daylight hours.
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, but the recommendations were not adopted.
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. The findings of the committee, which were presented to Parliament in 2004 by the Minister of 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.'
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 union and state governments to define and set the local time for a particular industrial area. In 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. Still, Indian Standard Time remains the only officially used time.
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Indian Standard Time
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.
The Indian Standard Time was adopted on 1 January 1906 during the British era with the phasing out of its precursor Madras Time (Railway Time), and after Independence in 1947, the Union 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. 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+05:30 as possible.
Daylight Saving Time (DST) was used briefly during the China–India War of 1962 and the Indo-Pakistani Wars of 1965 and 1971.
Indian Standard Time is calculated from the reference longitude of IST at 82°30'E passing near Vindhyachal of Mirzapur district in Uttar Pradesh. In 1905, the meridian passing east of Allahabad was declared as a standard time zone for British India and was declared as IST in 1947 for the Dominion of India. This longitude of 82°30'E was chosen as the standard meridian for the whole country as it is located centrally between western India (local time UTC +05:00) and northeastern India (local time UTC +06:00). Currently, the National Physical Laboratory of India maintains the Indian Standard Time with the help of the Allahabad Observatory.
The country's east–west distance of more than 2,933 kilometres (1,822 mi) covers over 29° of longitude, resulting in the sun rising and setting almost two hours earlier on India's eastern border than in the Rann of Kutch in the far west. Inhabitants of the northeastern states have to advance their clocks with the early sunrise to avoid the extra consumption of energy after daylight hours.
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, but the recommendations were not adopted.
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. The findings of the committee, which were presented to Parliament in 2004 by the Minister of 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.'
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 union and state governments to define and set the local time for a particular industrial area. In 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. Still, Indian Standard Time remains the only officially used time.