Population, , is a number used as a marker for the population and size of a city. The number is not literal. If a City has 1 population, or Citizen, it does not mean there is literaly only one person living there. It means the city is a very small village. If you have 10 citizens, you city is a metropolitan looking area. If it is 15 or 20, it is, of course, a gigantic city, and you have accomplished an impecable feat.