The Alerts are based on atomic clocks and synchronised with the worldwide system of clocks that support Coordinated Common Time. India's time zone is predicated over the 82.5°E meridian, which passes by Mirzapur. The fifty percent-hour offset was decided on to help keep the time near the indicate solar time https://ist-time-now98693.homewikia.com/12396938/the_5_second_trick_for_live_world_clock