Clause (c) refers so clauses (a), (b) and (c) of section 21 which defines Indian ships, and says: "For the purposes of this Act, a ship shall not be deemed to be an Indian ship unless owned wholly by persons to each to whom any of the following descriptions applies: (a) a citizen of India; or (b) a company which satisfies the following requirements, namely: (i) the principal place of business of the company is in India; (ii) at least seventy five per cent of the share capital of the company is held by citizens of India: Provided that the Central Government may, by notification in the official Gazette, alter such minimum percentage, and where the minimum percentage is so altered, the altered percentage shall, as from the date of the notification, be deemed to be substituted for the percentage specified in this sub clause; (iii) not less than three fourths of the total number of directors of the company are citizens of India; (iv) the chairmen of the board of directions and the managing director, if any, of the company are citizens of India; (v) the managing agents, if any, of the company are citizens of India or in any case where a company is the managing agent, the company satisfies the requirements specified in sub cls.