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DP Sengupta, 83, shuffles from living room to bedroom amidst a cacophony of ringing landline phones. Ignoring the calls, he scrounges, instead, for an Indian Express clipping from 1976. Ours is a telephonic chat, but one can still vividly picture the bald, bearded and baritoned scientist going from room to room during the conversation. Sengupta is former visiting professor at Bengaluru’s National Institute of Advanced Studies (NIAS) and emeritus fellow at the Indian Institute of Science. He’s also a critic of nuclear tests, an amateur ghazal singer and author of children’s science books.

But above all else, he’s an advocate for changing Indian Standard Time (IST).

Sengupta and research partner Dilip Ahuja, 68, were in Mumbai on 18 March for a talk at the Observer Research Foundation. The lecture, ‘Energy and non-energy consequences in adjustments in Indian Standard Time’, was their latest in a series on why IST should be pushed ahead by half an hour to UTC+6:00 instead of the current UTC+5:30. These lectures, spanning 10 years and about as many cities, from Thiruvananthapuram to Delhi, take off from their 2011 study—one which is almost always footnoted in articles or rebirthed in research papers about why India needs a modified IST.

Time is anything but objective. Our hours, minutes, and seconds are dictated by atomic clocks so precise, they won’t gain or lose a second in millions of years. Their exacting nature is why the International Bureau of Weights and Measures (BIPM) uses them to define UTC, or Coordinated Universal Time, as the basis for civil time. All countries, in turn, align to their assigned atomic clocks that march to the BIPM drum.

But even precision bends to the whims of our earth. The tilt of the planet’s axis, the churning of tectonic plates and the tides of the moon tease man-made time every now and then, reeling it in a perpetual game of catch-up. Here’s an example: the moon, through the power of tides, is slowing the earth’s rotation. This means our days are getting longer—by 2.5 milliseconds every century.

For satellites, aircraft, sportspeople and just about any kind of programming for which milliseconds are make or break, this is everything. The slower the earth gets, the faster the millisecond-gaps will pile up. In which case, a leap second will be added more regularly to the UTC than it is today.

If one millisecond can do this much, imagine the chronological chaos that once was in a country as extensive as this. India’s longitudes span 68° 7′ east to 97° 25′ east. That’s almost 30° of longitude, while time zones roughly change by one hour every 15°. The sun that rises at 4:30 AM in Arunachal Pradesh at the northeastern tip of the country rises at 6:30 AM in Gujarat in the west. If dusk awakens at 4:30 PM in our eastern flanks, it doesn’t do so until 6:30 PM in the west.


Roshni Nair

Roshni P. Nair joins us from Reuters, where she was an online producer. With a background in weekend features at Hindustan Times and DNA, Roshni has written on subjects ranging from India’s amateur UFO investigators to the provenance of sambhar. When not pursuing story ideas, she enjoys reading, making a great cuppa adrak chai, playing with street dogs, and avoiding large gatherings. Roshni will work out of Mumbai and can be reached at roshni at the rate

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