Section 211(5)(b) in The Building And Other Construction Workers '(Regulation Of Employment And Conditions Of Service) Central Rules, 1998
(b)on an application made by any part to the enquiry, the authority or the enquiry officer, as the case may be, referred to in sub-rule (1), if it or he is of the opinion that the holding of public enquiry will lead to disclosure of information relating to a trade secret, decides to hold the enquiry of such part of it in camera, such enquiry shall not be held in public.