Companies Act, 1956
Sec 151 - Index of members.
(1) Every company having more than fifty members shall, unless the register of members is in such a form as in itself to constitute an index, keep an index (which may be in the form of a card index) of the names of the members of the company and shall, within fourteen days after the date on which any alteration is made in the register of members, make the necessary alteration in the index.
(2) The index shall, in respect of each member, contain a sufficient indication to enable the entries relating to that member in the register to be readily found.
(3) The index shall, at all times, be kept at the same place as the register of members.
(4) If default is made in complying with sub-section (1), (2) or (3), the company, and every officer of the company who is in default, shall be punishable with fine which may extend to five hundred rupees.