The time difference between the westernmost part of India and the easternmost point is approximately two hours, the effect of which is that the sun rises and sets much earlier than it does in the rest of the country. A new analysis by the National Physical Laboratory (NPL) - India’s official timekeeper - has supported a long standing demand for a separate time zone for eastern states - Assam, Meghalaya, Nagaland, Arunachal Pradesh, Manipur, Mizoram, Tripura – and Andaman and Nicobar Islands. In the northeast region, the sun rises and sets ahead of the official working hours which are based on the Indian Standard Time (IST). In winters, the daylight hours are further shortened as the sun sets much early. This has adverse impacts on productivity and electricity consumption. In fact, tea gardens of Assam for long have been following ‘chaibagaan time’ which is one hour ahead of IST. In order to overcome difficulties in coping with IST, parliamentarians and other groups from the region have been demanding a separate time zone for the north east.

At present, the country observes a single time zone based on the longitude passing through 82°33′E.

The two different time zones takes the following into account : (1) impact of sunrise and sunset timings on biological activities of people; (2) synchronising sunrise and sunset timings with office hours; (3) minimisation of spatial extension at the proposed border of time demarcation; and (4) feasibility of technically managing two time zones.

The demand is based on the huge difference in daylight times between the country’s longitudinal extremes, and the costs associated with following the same time zone. East India would move an hour ahead, increasing the region’s productive, daylight hours and the country’s potential energy savings could amount to a whopping 20 million kWh a year. Offices could open sooner after sunrise, and perhaps workers could even savour the last dregs of dusk as they trudge towards home or their desired form of recreation. Biomedical research has consistently pointed to the physical and psychological benefits of aligning circadian (sleep) rhythms to the sun’s rising and setting.