Section 17(8)(c) in The Merchant Shipping (Crew Accommodation) Rules, 1960
(c)The Central Government may exempt;(i)any ship under 500 tons from any of the requirements of this sub-rules;(ii)any ship from the requirements of clause (b) of the sub-rule to the extent that it is satisfied that it is unreasonable or impracticable in the circumstances to remove obstructions above the beds in the crew accommodation of that ship.