Section 167(1)(iii) in The M.P. Motor Vehicles Rules, 1994
(iii)in the case of a double decked vehicle with an uncovered top deck, the top deck shall be provided with side rails and end rails the top of which shall be atleast ninety centimetres above the deck boards of battens at the modes and forty-five centimetres above the highest part of any seat, and the top of front and back rails shall be at least one hundred centimetres above the deck boards or battens and shall follow the chamber or the deck.