Section 38(1) in The Indian Port Health Rules, 1955
(1)The Health Officer may require any person on an international voyage who does not show sufficient evidence of protection by a previous attack of smallpox to possess on arrival, a certificate of vaccination against smallpox. Any such person who cannot produce such a certificate maybe vaccinated: if he refuses to be vaccinated, he may be placed under surveillance for not more than fourteen days, reckoned from the date of his departure from the last territory visited before arrival.
