Who started the Saka Era which is still used by the Government of India?

The beginning of the Shaka era is now widely equated to the ascension of king Chashtana in 78 CE. His inscriptions, dated to the years 11 and 52, have been found at Andhau in Kutch region. These years are interpreted as Shaka years 11 (89 CE) and 52 (130 CE). A previously more common view was that the beginning of the Shaka era corresponds to the ascension of Kanishka I in 78 CE.