[custom_adv] A minister is a politician who heads a government department, making and implementing decisions on policies in conjunction with the other ministers. [custom_adv] In some jurisdictions the head of government is also a minister and is designated the "prime minister", "premier", "chief minister", "Chancellor" or other title. [custom_adv] In Commonwealth realm jurisdictions which use the Westminster system of government, ministers are usually required to be members of one of the houses of Parliament or legislature, and are usually from the political party that controls a majority in the lower house of the legislature. [custom_adv] In some jurisdictions the head of government is also a minister and is designated the "prime minister", "premier", "chief minister", "Chancellor" or other title. [custom_adv] Lavasan is an affluent town in Shemiranat County, Capital Province. At the 2011 census, its population was 28,558, in 7,645 families. The Jajrood River flows through Lavasan.