(1)The Chairman and other members of a Public Service Commission shall be appointed, in the case of the Union Commission or a Joint Commission, by the President, and in the case of a State Commission, by the Governor of the State:Provided that as nearly as may be one-half of the members of every Public Service Commission shall be persons who at the dates of their respective appointments have held office for at least ten years either under the Government of India or under the Government of a State, and in computing the said period of ten years any period before the commencement of this Constitution during which a person has held office under the Crown in India or under the Government of an Indian State shall be included.