fter the decisive period for the Greek nation of 1912–1922, Piraeus experienced a major demographic explosion, with its population almost doubling to reach 251,659 in 1928 from 133,482 in 1920, an increase owed to the arrival of Greek refugees from Asia Minor after the Greco-Turkish War and the Asia Minor Catastrophe. Although there was an increase in the labour force, a variety of social problems also emerged with the concentration of new populations in the suburbs of the old city, such as Nikaia, Keratsini, Drapetsona and Korydallos.
The involvement of Greece in World War II came as a major setback to the city's progress. After the war, the city began its development once more, as damage to the port and the city were repaired and new additions took shape after 1955. Piraeus is now the third largest municipality in Greece; the city proper with its suburbs form the Piraeus urban area, which is incorporated in the Athens urban area, thus making Piraeus an integral part of the Greek capital. The port of Piraeus is now an important international port, and the largest in the country
