law: National Environment Appellate Authority Act, 1997
  6. Vice-Chairperson to act as Chairperson or
  
  to discharge his function in certain circumstances- 
  (1) In the event of the occurrence of any
  
  vacancy in the office of the Chairperson by reason of his death, resignation or
  
  otherwise, the Vice-Chairperson shall act as the Chairperson until the date on which
  
  a new Chairperson appointed in accordance with the provisions of this Act to
  
  fill such vacancy enters upon his office.
  (2) When the Chairperson is unable to
  
  discharge his functions owing to absence, illness or any other cause, the
  
  Vice-Chairperson or, as the case may be, such one of the Member as the Central
  
  Government may, by notification, authorize in this behalf, shall discharge the
  
  functions of the Chairperson until the date on which the Chairperson resumes
  
  his duties.