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What Is Indian Standard Time IST, Its Importance, Time Zone and Much More

what is Indian standard time IST
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Indian Standard Time means the time zone that is followed throughout India. Have you ever come across a situation where you wondered, what is Indian standard time IST and what is its importance? The simple answer to these questions is that since various states within India fall on a different meridian, there will be differences in their local time. So, to give uniformity to the entire country, Indian Standard Time IST was framed. This brings us to the next big question, what is Indian Standard Time zone and what is the standard meridian of India? For India, 82° 1/2 E is the longitude and is known as the standard meridian of India. Continue reading to know more about Indian Standard Time.

What Does Indian Standard Time Means?

Wondering what is Indian standard time IST? Below discussed questions will enable you to understand what Indian Standard Time means and its uses in a clear manner.

What Is Indian Standard Time IST And What Does It Mean?

After India got Independence, the former government wanted to establish a uniform time throughout India. So, on the 1st of September 1947, the IST was introduced. Indian Standard Time means the official standard time of the entire nation. This is everything you need to know about what is Indian Standard Time IST all about.

What Is Indian Standard Time zone?

Several countries follow different time zones. India follows a single time zone. This time zone has been followed since the year 1947. The distance between the west and the east of India is around 3,000 kilometres. And India would have 3 time zones if it was on the mean solar time. Since 1906, India has been following the local time as UTC + 5:30. This is all you need to know about what is Indian Standard Time zone.

What Is The Standard Meridian Of India?

The standard meridian of India considers 82° 30’E as the longitude. 

What Is The Standard Meridian Of India And Why Is It Needed?

Different states in India fall into different meridians and have distant local times. Because of this reason, there is a two-hour time lag from the state of Gujarat to Andhra Pradesh. And this is why the standard meridian passing through Mirzapur and the state of Uttar Pradesh is considered to be the standard time followed throughout India.82°30’E longitude is where the meridian, what is the standard meridian of India, passes.

what is the standard meridian of India
Source- Wikipedia

If the same time is followed by all the people in India, there would be huge confusion and a lot of problems arising because of that. Having the standard meridian time saves a lot of trouble for all Indian citizens. So the next time someone asks you ”what is the standard meridian of India”? Be sure to explain it to them clearly. 

Why Did India Adopt Indian Standard Time?

In the year 1850, the railway time system was introduced. Before that, the Indian citizens were following the local reference time. After the arrival of train stations, it was a necessity to follow a uniform time throughout India to avoid confusion regarding the boarding and departure of the vehicle. This was the reason why did India adopt Indian Standard Time.

Where Is Indian Standard Time Located?

In India, the place where Indian Standard Time is located in Mirzapur. The Mirzapur clock tower calculates what is Indian Standard Time IST.

Longitude Of Indian Standard Time

The Indian Standard Time (IST) calculated from the Mirzapur clock tower has a longitude value of 82°30’E and four angular minutes.


After learning what is Indian Standard Time zone, it might seem to include different things and find it quite confusing when for the first time. But once you know what Indian Standard Time means, understand its use and what is its importance, you will find it very easy to remember. 

To summarise, the Indian Standard Time means the uniform time accepted and followed by the entire country to avoid any form of confusion regarding the time inside the county or worldwide.


Here are a few commonly asked questions regarding the IST system of India.

1. When Was Indian Standard Time Adopted?

The Union Government established the IST system after the independence of India. In the year 1947, on the 1st of September, Indian Standard Time was adopted.

2. Who Invented Indian Standard Time?

Astronomer John Goldingham invented Indian Standard Time IST. He was the first one to compute the longitude as five hours and 30 minutes which is ahead of the GMT (Greenwich Mean Time) for Madras. 

3. Who Maintains Indian Standard Time?

Indian Standard Time is maintained by CSIR-NPL. The clocks of CSIR-NPL are known to be so accurate, that those clocks would gain or lose a second every 3 lakh years. 

4. Which Countries Follow Indian Standard Time?

Only Sri Lanka apart from India follows the IST system.

5. How Many Time Zones Are There In India?

India has only a one-time zone. This single time zone is followed by Sri Lanka as well.

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