Holding of inquiry requires notice and hearing; adjudicating officer may summon witnesses and proceed in absentia. Holding of inquiry requires the adjudicating officer to issue a notice to show cause and indicate the nature of the alleged contravention; if proceeding, the officer fixes a date for appearance, explains the alleged offence and relevant provisions, allows production of documents and evidence (not bound by the Evidence Act), may summon witnesses and compel documents, and may continue the inquiry after recording reasons if the person fails to appear.