Necessity of ‘Two Time Zones: IST-I (UTC + 5 : 30 h) and IST-II (UTC + 6 : 30 h)’ in India and Its Implementation

A strong demand of a separate time zone by northeast populace has been a matter of great debate for a very long period. However, no implementable solution to this genuine problem has yet been proposed. The CSIR-National Physical Laboratory, CSIR-NPL (the National Measurement Institute, NMI, of India and custodian of Indian Standard Time, 1ST) proposes an implementable solution that puts the country in two time zones: (1) IST-I (UTC + 5 : 30 h, represented by longitude passing through 82 degrees 33E) covering the regions falling between longitude 68 degrees 7 E and 89 degrees 52 E and (ii) IST-II (UTC + 6 : 30 h, represented by longitude passing through 97 degrees 30 E) encompassing the regions between 89 degrees 52 E and 97 degrees 25 E. The proposed demarcation line between IST-I and IST-II, falling at longitude 89 degrees 52 E, is derived from analyses of synchronizing the circadian clocks to normal office hours (9 : 00 a.m. to 5 : 30 p.m.). This demarcation line passes through the border of West Bengal and Assam and has a narrow spatial extension, which makes it easier to implement from the railways point of view. Once approved, the implementation would require establishment of a laboratory for 'Primary Time Ensemble - II' generating IST-II in any of the north-eastern states, which would be equivalent to the existing 'Primary Time Ensemble-I' at CSIR-NPL, New Delhi.