As people moved from rural areas to the cities, there were fewer people to grow food for the population.
Originally all supplies had to be moved from other areas as the settlements were being established.
It began with the black Cubans who had moved to the cities from rural areas.
People began to move from rural areas into the new industrial towns.
Between 1830 and 1860, thousands of farm girls moved from rural areas where there was no paid employment to work in the nearby mills.
Problems would arise, of course, with addicts moving in from other areas of the country.
People moved to the village from other areas of the island to be near the school.
If we stop that trade, animals will still move to Lebanon, perhaps from Australia and other areas.
In Malaya the strategy involved moving half a million people from insurgent areas.