Rural flight (or rural exodus) is the migratory pattern of peoples from rural areas into urban areas. It is urbanization seen from the rural perspective. In industrializing economies like Britain in the eighteenth century or East Asia in the twentieth century, it can occur following the industrialization of primary industries such as agriculture, mining, fishing, and forestry—when fewer people are needed to bring the same amount of output to market—and related secondary industries (refining and processing) are consolidated. Rural exodus can also follow an ecological or human-caused catastrophe such as a famine or resource depletion. These are examples of push factors.