The national calendar of India is based on the Saka Era with Chaitra as its first month and a normal year of 365 days. The national calendar of India was adopted on March 22nd 1957. Dates of the Indian national calendar have a permanent correspondence with the Gregorian calendar dates- 1 Chaitra falling on 22 March normally and on 21 March in leap year.
The national Calendar of India is used along with the Gregorian
calendar for the following official purposes- (i) Gazette of India, (ii)
news broadcast by All India Radio, (iii) calendars issued by the
Government of India and (iv) Government communications addressed to the
members of the public.