When did Japan begin to introduce environmental protection laws ?
The " Leprosy Prevention laws " of 1907 , 1931 and 1953 , the last one only repealed in 1996 , permitted the segregation of patients in sanitaria where forced abortions and sterilization were common , even if the laws did not refer to it , and authorized punishment of patients " disturbing peace " as most Japanese leprologists believed that vulnerability to the disease was inheritable .