Urban Development in South Korea 11 indicators covering urban development for South Korea. IndicatorLatest Year10-yr change Rank Population in the largest city 23.9% 2025 up 0.6% 100th Population density 529.84 people per sq. km of land area 2023 up 2.4% 24th PM2.5 air pollution, mean annual exposure 21.89 micrograms per cubic meter 2023 down 12.6% 73rd Population in urban agglomerations of more than 1 million 26.41 million 2025 up 3.6% 15th Population in urban agglomerations of more than 1 million, per capita 0.511 units per person 2025 up 2.2% 12th Population in urban agglomerations of more than 1 million, annual 0.2996 % change on previous year 2025 down 40.1% 105th Population in urban agglomerations of more than 1 million, per unit 0 units per US$ of GDP 2025 down 14.9% 89th Population in urban agglomerations of more than 1 million, per square 269.03 units per square kilometre 2023 up 3.8% 4th Population in largest city 10.03 million 2025 up 1.3% 22nd PM2.5 air pollution, population exposed to levels exceeding WHO 100.0% 2017 unchanged 1st Adjusted rural to urban parity index for achieving a minimum 0.9113 2012 up 8.0% 15th