Indian Standard Time (IST) is the time observed throughout India and Sri Lanka, with a time offset of UTC+05:30. India does not observe Daylight Saving Time (DST) or other seasonal adjustments. In military and aviation time, IST is designated E* ("Echo-Star").

Indian Standard Time is calculated on the basis of 82.5° E longitude, from a clock tower in Mirzapur (25°09′N 82°35′E / 25.15°N 82.58°E / 25.15; 82.58) (near Allahabad in the state of Uttar Pradesh) which is nearly on the corresponding longitude reference line.

In the IANA time zone database it is represented by Asia/Kolkata.

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 Bombay Time) until 1955. The Central observatory was moved from Chennai to a location near Mirzapur, so that it would be as close to UTC +5:30 as possible.

Daylight Saving Time (DST) was used briefly during the Sino–Indian War of 1962 and the Indo–Pakistani Wars of 1965 and 1971.

Standard time is the result of synchronizing clocks in different geographical locations within a time zone to the same time rather than using the local meridian as in local mean time or solar time. Historically, this helped in the process of weather forecasting and train travel. The concept became established in the late 19th century. The time so set has come to be defined in terms of offsets from Universal Time. Where daylight saving time is used, the term standard time typically refers to the time without daylight saving time.

The adoption of Standard Time, because of the inseparable correspondence between time and longitude, solidified the concepts of halving the globe into an eastern and western hemisphere, with one Prime Meridian (as well its opposite International Dateline) replacing the various Prime Meridians that were in use.

A standardized time system was first used by British railways on December 11, 1847, when they switched from local mean time to Greenwich Mean Time (GMT). It was also given the name Railway time reflecting the important role the railway companies played in bringing it about. The vast majority of Great Britain's public clocks were being synchronised using GMT by 1855.

Farahnaz Ispahani (Urdu: فرح ناز اصفهانی) was serving as a member of the National Assembly of Pakistan until her membership got suspended by the supreme court and as a spokesperson for the President of Pakistan, Asif Ali Zardari. She is married to Husain Haqqani, the former Pakistan Ambassador to the United States, and is the granddaughter of Pakistan's first ambassador to the United States, Mirza Abol Hassan Ispahani. Her uncle, Zia Ispahani has also served as a politician and former ambassador for Pakistan. Ispahani was born in Karachi, and grew up in Karachi, Dhaka and London. She graduated from Wellesley College in Massachusetts, majoring in political science.

Ispahani spent two decades in journalism -- both print and television -- before entering politics. She worked in broadcasting, working with MSNBC, CNN, (ABC) and (VOA) assisting in the launch of new programs including CNN's Paula Zahn Now and Anderson Cooper 360°. In addition, she served as the Managing Editor and Executive Producer for the Voice of America Urdu language television program Beyond the Headlines. She served as Editor Special Reports for the leading Pakistani news magazine The Herald, and was the Editor of Zameen, a magazine oriented toward Pakistanis living abroad. She is a regular contributor in The News, Pakistan's second largest English-language newspaper.