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, o f India and custodian o f Indian Standard Time, IST) proposes an implementable solution that puts the country in two time zones: (i) IST-I (UTC + 5: 30 h, represented by longitude passing through 82 °33 E) covering the regions falling between longitude 68 °7 E and 89 °52 E and (ii) IST-II (UTC + 6: 30 h, represented by longitude passing through 97°30E) encompassing the regions between 89°52E and 97°25E. The proposed demarcation line between IST-I and IST-II, falling at longitude 89 °52 E, is derived from analyses o f synchronizing the circadian clocks to normal office hours (9: 00 a.m. to 5 : 30p.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 o f view. Once approved, the implementation would require establishment of a laboratory for ‘Primary Time Ensemble - I I ’ generating IST-II in any o f the north-eastern states, which would be equivalent to the existing ‘Primary Time Ensemble-I’ at CSIR-NPL, New Delhi.