law: Factories Act, 1948 
  14. Dust and fume 
  (1) In every factory in which, by reason of the manufacturing
  
  process carried on, there is given off any dust or fume or other impurity of
  
  such a nature and to such an extent as is likely to be injurious or offensive to
  
  the workers employed therein, or any dust in substantial quantities, effective
  
  measures shall be taken to prevent its inhalation and accumulation in any
  
  workroom, and if any exhaust appliance is necessary for this purpose, it shall
  
  be applied as near as possible to the point of origin of the dust, fume or
  
  other impurity, and such point shall be enclosed so far as possible.
  (2) In any factory no stationary internal combustion engine
  
  shall be operated unless the exhaust is conducted into the open air, and no
  
  other internal combustion engine shall be operated in any room unless effective
  
  measures have been taken to prevent such accumulation of fumes there from as
  
  are likely to be injurious to workers employed in the room.