The national calendar based on the Saka Era, with Chaitra as its first month and a normal year of 365 days was adopted from 22 March 1957 along with the Gregorian calendar for the following official purposes:
- Gazette of India.
- News broadcast by All India Radio.
- Calendars issued by the Government of India.
- Government communications addressed to the members of the public.
Dates of the national calendar have a permanent correspondence with dates of the Gregorian calendar, 1 Chaitra falling on 22 March normally and on 21 March in leap year.
Source: India Book - A Reference Annual