Section 11(3) in The Official Languages (Use For Official Purposes Of The Union) Rules, 1976
(3)All name-plates, sign boards, letter-heads and inscriptions on envelopes and other items of stationery written, printed or inscribed for use in any Central Government office shall be in Hindi and in English:Provided that the Central Government may, that is considered necessary to do so by general or special order exempt any Central Government Office from all or any of the provisions of this rule.
