Section 19(2) in U.P. Industrial Disputes Rules, 1957
(2)Where there are numerous persons as parties to any proceeding before a Board, Labour Court, Tribunal or an Arbitrator and such persons are not members of any Union or Association the Board, Labour Court, Tribunal or Arbitrator, as the case may be, shall, where in its/his opinion, personal service is not practicable, cause the service of any notice to be made by affixing the same at or near the main entrance of the establishment concerned and in such other manner as the Board, Labour Court, Tribunal or Arbitrator may deem fit and proper. A notice exhibited in such manner shall also be considered as sufficient in the case of such workmen as cannot be ascertained and found.
