If you have ever travelled from Kolkata to Mumbai, you have likely noticed that daylight arrives later in the morning in Mumbai than in Kolkata, and sunlight lasts later into the evening. On the other hand, if you travel further east to the eastern edge of Assam, light dawns as early as 4:30 am in summer and it gets dark by around 4 pm in winter. This is why the northeastern states have for a long time been demanding that they have a timezone distinct from the Indian Standard Time (IST), so they can take advantage of the early daylight hours.
Countries across the world keep different times because of Earth’s rotation and revolution around the Sun. As Earth turns by 15° around its axis, time changes by one hour; a 360º-degree rotation yields 24 hours. As a result, the world is divided into 24 timezones shifted by one hour each. However, although the timezones are demarcated by the longitudes, each timezone is not always a straight line cutting through a country. The zones are determined by the governments after accounting for their geography, and the official time of a country is maintained by the respective governing authorities.
In India, the IST is based on longitude 82.5°, which passes through Mirzapur, near Allahabad in Uttar Pradesh, and is 5 hours 30 minutes ahead of Greenwich Mean Time (GMT), now called the Universal Coordinated Time (UTC). The keeper of the time in India is the CSIR-National Physical Laboratory (NPL), New Delhi, which records time using five caesium atomic clocks. This time has an accuracy of 20 nanoseconds and is traceable to the UTC provided by the International Bureau of Weights and Measures in Sèvres, France.
Also read: From Sundials to Atomic Clocks, a Journey Through the Way Humans Have Kept Time
The idea of two timezones for India – spanning from about 68° E to 97° E, equivalent to two timezones in the east-west direction – is not new. In 1884, when timezones across the world were being established, it was decided that India would have two times: Bombay time, 4 hours 51 minutes ahead of GMT, and Calcutta time, 5 hours 30 minutes ahead of GMT. However, in 1905, the British adopted a single timezone for India using the 82.5° meridian.
But the issue of two timezones kept cropping up. Last year, the Gauhati high court dismissed a public interest litigation seeking direction from the Centre to notify a separate timezone for the Northeast. A high-level committee constituted by the Department of Science and Technology had looked into this earlier and recommended that a single timezone be maintained, and the court based its decision on this recommendation.
Now, researchers at the CSIR-NPL have reopened this argument. In a new study, they argue for two timezones in India. They propose a demarcation passing through 89°52’ E, at the border between West Bengal and Assam – the ‘narrowest’ part of the country, sandwiched between Nepal on the west and Bangladesh on the east.
Regions to the west of this line would be 5 hours 30 minutes ahead of UTC and regions east of this line, including the northeastern states, would be time 6 hours and 30 minutes ahead of UTC. The authors say that choosing this thin piece of land would cause the least disruption, especially as related to the management of railways, and be easier to implement.
“If the decision is to have two time zones in the country, the chicken’s neck area is the best place through which [to] pass the demarcation line,” D.R. Ahuja, who studies science and technology policy at the National Institute of Advanced Studies (NIAS), Bengaluru, said.
There are several reasons why researchers, as distinct from governments, ask for two timezones. One is that people’s productivity and efficiency follows a biological clock that is synchronised with the daily light-dark cycles, with daylight hours best suited for working and the night for resting. The body secretes a hormone, melatonin, a few hours after dark, getting the body ready for sleep and continues secretion until about just after sunrise. Only some time after melatonin secretion stops is the body at its highest level of mental and physical alertness. Hence, work is done with the greatest efficiency during daylight hours.
The shortest period of daylight occurs in winter, from about 6 am to 4 pm in the Northeast, whereas the western part of the country enjoys daylight typically between 7 am and 6 pm. This leaves a person working in the Northeast after sunset (assuming working hours are from 9 am to 6 pm), when the body is physiologically readying to rest and one’s efficiency is lower than normal.
In addition, working in the dark requires artificial lighting, increasing energy consumption. The researchers estimate an annual energy savings of 20 million kWh if two timezones are implemented.
“The authors of the paper have done a fairly thorough job, their main objective has been to increase efficiency of the populace by synchronising office hours with efficiency,” D.P. Sen Gupta, an emeritus professor at the Indian Institute of Science, Bengaluru, and currently at NIAS, explained. However, he did point out that apart from physiological mechanisms, there are also as cultural and physical factors, differences in work ethics, and compulsions in the public and private sectors that determine productivity. So while it stands to reason that assigning a new timezone to the Northeast will influence productivity, it may not necessarily be significant.
Also read: How Do You Tell Time in the Lands of the Midnight Sun?
Nonetheless, “Our main concern about dividing the country into timezones has been and continues to be political,” Gupta said. With the several divisive forces now at play, “can we afford to introduce yet another element of division such as two timezones when holding the country together is becoming a problem?”
Ahuja seconded this point of view. “The main objection to having two timezones is political – the reinforcing of the feeling [in] the Northeast that it is a separate region from the rest of the country.” There are also other disadvantages of having two timezones, such as mismatch in office timings, different working hours for banks and a chance that railway accidents might become more frequent – but none of these are insurmountable. Ahuja also said that the energy savings will be minuscule considering the Northeast uses much less energy than the rest of the country.
In 2011, Sengupta and Ahuja had conducted a study that found energy savings would be greatest if the IST were advanced by 30 minutes while still maintaining a single timezone for the entire country – compared to if there were two timezones. In addition, this would resolve issues faced by the population of the Northeast vis-á-vis utilising daylight hours efficiently while minimising adverse impacts for the whole country.
All this said, the Government of India has been and remains reluctant to change the status quo. Whether the new study will change the government’s point of view remains to be seen.
Lakshmi Supriya is a freelance science writer based in Bengaluru.