The Signals are based on atomic clocks and synchronised With all the worldwide technique of clocks that aid Coordinated Universal Time. India's time zone is based over the 82.5°E meridian, which passes by Mirzapur. The 50 %-hour offset was preferred to keep the time close to the indicate solar time https://isttime33648.wikiannouncement.com/10622141/the_gmt_to_ist_diaries