The term "3 MPO" is not clear and there is no information available in the search results to determine what it refers to in Pakistan. However, the search results show that "MPO" stands for "Maintenance of Public Order" and is an ordinance that allows the government to arrest and detain suspected persons. The ordinance was first promulgated as the West Pakistan Maintenance of Public Order in 1960 during the military dictatorship of Pakistan. Section 3 of the ordinance gives the government the power to arrest and detain suspected persons.