Hindi was adopted as one of the two official languages of the Republic of India by the Constituent Assembly on 14 September, 1949. Among those who lobbied to make hindi an official language were Beohar Rajendra, Hazari Prasad Dwivedi, Kaka Kalelkar, Maithili Sharan Gupt and Seth Govind Das. The decision was ratified by Constitution of India that came into effect on the 26th of January 1950, and under Article 343 of the Indian Constitution, Hindi is recognised as an official language.
The official language of the Union shall be Hindi in the Devanagari script. The form of numerals to be used for the official purpose of the Union shall be the international form of Indian numerals.