law: Companies Act, 2013 
  161.
  
    Appointment
  
  of additional director, alternate director and nominee director.
  1.      The articles of a
  
  company may confer on its Board of Directors the power to appoint any person,
  
  other than a person who fails to get appointed as a director in a general meeting,
  
  as an additional director at any time who shall hold office up to the date of
  
  the next annual general meeting or the last date on which the annual general
  
  meeting should have been held, whichever is earlier.
  2.      The Board of
  
  Directors of a company may, if so authorised by its articles or by a resolution
  
  passed by the company in general meeting, appoint a person, not being a person
  
  holding any alternate directorship for any other director in the company, to
  
  act as an alternate director for a director during his absence for a period of
  
  not less than three months from India:
  Provided
  
  that no person shall be appointed as an alternate director for an independent
  
  director unless he is qualified to be appointed as an independent director
  
  under the provisions of this Act:
  Provided
  
  further that an alternate director shall not hold office for a period longer
  
  than that permissible to the director in whose place he has been appointed and
  
  shall vacate the office if and when the director in whose place he has been appointed
  
  returns to India:
  Provided
  
  also that if the term of office of the original director is determined before
  
  he so returns to India, any provision for the automatic re-appointment of
  
  retiring directors in default of another appointment shall apply to the
  
  original, and not to the alternate director.
  1.     
  2.     
  3.      Subject to the
  
  articles of a company, the Board may appoint any person as a director nominated
  
  by any institution in pursuance of the provisions of any law for the time being
  
  in force or of any agreement or by the Central Government or the State
  
  Government by virtue of its shareholding in a Government company.
  4.      In the case of a
  
  public company, if the office of any director appointed by the company in
  
  general meeting is vacated before his term of office expires in the normal
  
  course, the resulting casual vacancy may, in default of and subject to any
  
  regulations in the articles of the company, be filled by the Board of Directors
  
  at a meeting of the Board:
  Provided
  
  that any person so appointed shall hold office only up to the date up to which
  
  the director in whose place he is appointed would have held office if it had
  
  not been vacated.