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.

Mohammad Umer Daudzai (Pashto: محمد عمر داودزی - born October 12, 1957), is the Chief of Staff of Afghan President Hamid Karzai from 2003 to 2005 and then from 2007 to present. He is a former member of the Hezbi Islami and was from 2005 until 2007 Afghan's Ambassador in Iran.

Mohammad Omar Daudzai was born on October 12, 1957 in the Qarabagh District of the Kabul Province in Afghanistan. He grew up and completed his primary education in his home district of Qarabagh. In order to continue his higher education, Omar moved to the capital city Kabul.

During the 1980s Daudzai became active in the resistance against the Sovjet-occupation and joined the Mujahideen group of Gulbuddin Hekmatyar: Hezbi Islami. Also during the Civil War he kept fighting with the Pakistan backed Hezbi Islami to take over the country.

During the Taliban era Daudzai decided to settle in Peshawar, Pakistan, and began working for the organization Save the Children. While working there through a scholarship program, he was able to go to the Oxford University in the United Kingdom for his Masters in Science. After completing his Masters he came back to work for the Swedish Committee in Jalalabad, Afghanistan. In 1996 he moved to Islamabad, Pakistan, where he started working for the United Nations Development Program (UNDP). In 2001 he moved to Geneva, Switzerland, where he assumed the role of "Area Development Specialist" in UNDP Geneva.

Abdullah Abdullah (Persian: عبدالله عبدالله‎, born 1960) is an Afghan politician and a doctor of medicine. He was an adviser and friend to Ahmad Shah Massoud, legendary anti-Taliban leader and commander known as the "Lion of Panjshir". After the fall of the Taliban regime, Dr. Abdullah served as Afghanistan's Foreign Minister from 2001 until 2005. In 2009 Abdullah ran as an independent candidate in the Afghan presidential election and came in second place with 30.5% of the total votes. On November 1, 2009, Abdullah quit the runoff election that would have taken place six days later, on November 7, due to large-scale allegations of fraud against his opponent Hamid Karzai. In 2010, Abdullah created the Coalition for Change and Hope which is the leading democratic opposition movement in Afghanistan. In 2011, the coalition was transformed into the National Coalition of Afghanistan which is supported by dozens of Afghan political parties and members of parliament challenging the government of Hamid Karzai.

Amrullah Saleh (Persian: امرالله صالح; born 1971) is an Afghan politician who last served as head of the Afghan National Directorate of Security. In 1997, at the age of 24, he was appointed by anti-Taliban leader Ahmad Shah Massoud to lead the United Front's (Northern Alliance) liaison office inside the Afghan Embassy in Dushanbe handling contacts to international non-governmental (humanitarian) organizations and intelligence agencies. After the fall of the Taliban regime, Saleh was appointed by President Hamid Karzai in early 2004 to lead the National Directorate of Security. Due to political differences with Karzai, Saleh resigned his position in 2010. He is currently leading one of the strongest Afghan pro-democracy and anti-Taliban movements, the Basej-i Milli (National Movement) or Afghanistan Green Trend, with about 10,000 of his supporters rallying against the Taliban in Kabul in 2011.

Amrullah Saleh was born in the Panjshir Province of Afghanistan in 1971.

In the late 1990s, in his early 20s, Saleh worked for the anti-Taliban resistance, the United Front (Northern Alliance), under Ahmad Shah Massoud. In 1997, Saleh was appointed to lead Massoud's international liaison office in Dushanbe, Tajikistan, where he served as a coordinator for non-governmental (humanitarian) organizations and as a liaision partner for foreign intelligence agencies.