Section 40(a) in The Tamil Nadu Building and other Construction Workers (Regulation of Employment and Conditions of Service) Rules, 2006
(a)When an internal combustion engine exhaust into a confined space or excavation or tunnel or any other work place where neither natural ventilation nor artificial ventilation system is adequate to keep the carbon monoxide content of the atmosphere below fifty parts per million, or 55 mgm/m3 adequate and suitable measures are taken at such work place in order to avoid exposure of building workers to health hazards;
