A walk through Indian time from Ujjain to Mirzapur via Greenwich

Some 16 to 17 centuries ago, the line of longitude passing through Ujjain, located 72°46’ east of Greenwich, was considered the line of zero longitude by Indian astronomers. This was the meridian that Madhya Pradesh chief minister Mohan Yadav was referring to when he asserted that Ujjain is the “global prime meridian” and promised to “correct the time of the world”. The inhabitable world existed north of the equator between Yavanapura and Yamakoti.. Today, Indian Standard Time is based on the line of longitude through Mirzapur, a little under 10° east of Ujjain. This time zone was eventually phased out in 1906, when the British adopted Indian Standard Time based on a meridian through Allahabad, roughly 5:30 hours ahead of Greenwich. It goes without saying that Mirzapur’s longitude of 82°30’ is based on the prime meridian at Greenwich, not Ujjain.