law: 4. Power of Central Government to authorise the exercise of powers specified in section 5.-
  (1) Where the Central Government is of opinion that for the purposes of any departmental inquiry it is necessary to summon as witnesses, or call for any document from, any class or category of persons, it may, by notification in the Official Gazette, authorise the inquiring authority to exercise the power specified in section 5 in relation to any person within such class or category and thereupon the inquiring authority may exercise such power at any stage of the departmental inquiry.
  (2) The power conferred on the Central Government by sub-section (1) may also be exercised by such authority, not being an authority inferior to the appointing authority in relation to the person against whom the departmental inquiry is being held, as the Central Government may, by notification in the Official Gazette, specify in this behalf.