In June 2017, Department of Science and Technology (DST) indicated that they are once again studying feasibility of two time zones for India. However, the proposal would need to be cleared by the Union Government. In 2014, Chief Minister of Assam Tarun Gogoi started campaigning for another time zone for Assam and other northeastern states of India.
Still Indian Standard Time remains the only officially used time. 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. 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. 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." 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 binary system that they suggested involved a return to British-era time zones the recommendations were not adopted. In the late 1980s, a team of researchers proposed separating the country into two or three time zones to conserve energy. Inhabitants of the northeastern states have to advance their clocks with the early sunrise to avoid the extra consumption of energy after daylight hours. 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 in the far west. Currently, the Council of Scientific and Industrial Research- National Physical Laboratory (CSIR-NPL) maintains the Indian Standard Time with the help of the Allahabad Observatory. The longitude of 82★'E passing through Naini near Allahabad was chosen as the standard meridian for the whole country, because there is a time lag of more than an hour between western India ( around +05:00) and northeastern India ( around +06:00), hence approximately standardizing with UTC+05:30 of central India. 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. Indian Standard Time is calculated from the clock tower in Mirzapur nearly exactly on the reference longitude of IST at 82☃0'E, within 4 angular minutes. What difference does it make in a day and date if IDL is crossed.Location of Mirzapur (near Allahabad) and the 82.5° E longitude that is used as the reference longitude for IST In other words, IDL is drawn in such a way to avoid passing over the land. In order to pass IDL only on ocean areas, IDL is turned to the east or the west of 180°. The day and date is always ahead by one day in the west of International Date Line than the day and date running in the east of International Date Line.Īlthough the IDL is drawn with reference to 180° Meridian, International Date Line is not a straight line like 180° Meridian. International Date Line is an imaginary line drawn to the opposite of Greenwich Prime Meridian, i.e.
International Date Line is decided to overcome this confusion of 24 hour difference.It creates a difference of almost a day or 24 hours between the timing in the East and West of 180° Meridian.Same time, it is 2-2 hours behind the Greenwich time at every 30° latitude to the West of Greenwich.As a result of this ahead or behind timing, when it is Sunday noon at Greenwich, Sunday is just beginning to the east of 180° meridian and it is the end of Sunday in the west of 180° Meridian.When it is exactly noon i.e.12 o’clock afternoon on Greenwich, the time is ahead by 2-2 hours at every 30° latitude to the east of Greenwich.Therefore, the eastern part of the earth is always ahead of Western part. Earth completes one rotation in 24 hours.Man had studied the natural phenomena like Rotation, Revolution and develop the chronometric system for his purpose.