The indivisibility of Indian Standard Time is a myth.
It is time to take time seriously. Indian Standard Time discriminates against Assam,putting the daylight hours there out of gear with the circadian clock. The region has frequently demanded a different time zone ahead of IST,in which the nine to five working day would be in sync with the sun and teatime would arrive reliably at,well,teatime. But this simple demand was presumably sacrificed at the altar of national unity. One nation,one people,one time zone and no complaining.
The western and eastern extremities of India are separated by just four minutes short of two hours. In the interest of practicality,the country could be divided into two time zones,perhaps centred on Mumbai and Kolkata,which are separated by one hour and three minutes of real time. Indeed,Bombay Time and Calcutta Time were defined in 1884 and the latter survived until 1948,when it was superseded by IST. Calcutta Time was 24 minutes ahead of IST but now,Assam proposes to adopt the old,unofficial bagan time,which is a whole hour ahead and was designed to allow tea gardens to get their work done by daylight alone.
The efficiency dividend of time-zoning is so obvious that were it not for the symbolic demands of national unity,India may have been zoned in 1948. But now,an equally urgent imperative may force the issue. In an energy-poor country,power saving is a compelling argument,and two times zone will slash bills substantially. Three time zones including Assam would be even more efficient. But wait! What if China retaliates by decreeing that it will henceforth be the same time in Lhasa and Tawang? Politics,ugly politics,just biding its time.