Seoul is suffering the sharpest population decline among Korea's 17 municipalities, data showed on Monday, as many people can't afford to buy a home in the nation's capital and subsequently are moving to less central areas in search of cheaper housing. Most of the major cities and provinces also have been losing population. But it is more associated with the low birthrate and aging society that has been dealing a blow to the entire country, whereas the shrinking population in Seoul is mainly caused by a housing bubble, according to sources.