Why India is Half an Hour Off Global Time Zones

Ujjain, Madhya Pradesh, in 4th century India was a zenith of invention and scientific discovery. Ujjainis looked to an ancient astronomical text called the Surya Siddhanta as gospel. Their magnum opus measured time not in seconds, minutes, or hours, but rather prāṇa, or the time it took to complete one breath — equivalent to about four seconds. Six prāṇas, or 24 seconds, made up a pala, or the second smallest unit of time, and 60 ghalikās made up one day. The Ujjainis, one of the first to posit that a 24-hour day, examined thousands of people to establish an average of 15 breaths per minute, a value that still exists in modern medicine. 

It’s safe to assume that the ancient Ujjainis never fathomed that over 1,600 years later, many of their descendants would use clocks instead of their own bodies to tell time. And, on top of that, if they wanted to tell the time of a distant place, they might use another instrument altogether.

The concept of time zones is a relatively recent phenomenon, emerging in the late 19th century. But while the majority of the world has followed Greenwich Meridian Time (GMT), which divides the globe into 24 time zones in one-hour increments — with the central longitude going through Greenwich, England — India, Sri Lanka, Nepal, Afghanistan, Myanmar, and a few other countries have clocked out of such standards.