Motor Vehicles Act 1988
Section 128 :
Safety measures for drivers and pillion riders :
(1) No driver of a two-wheeled motor cycle shall carry more than one person in addition to himself on the motor cycle and no such person shall be carried otherwise than sitting on a proper seat securely fixed to the motor cycle behind the drivers seat with appropriate safety measures.
(2) In addition to the safety measures mentioned in sub-section (1), the Central Government may, prescribe other safety measures for the drivers of two-wheeled motor cycles and pillion riders thereon.