Under the Republic, the county was organized first under the Nantong and then the Songjiang Special Administration District. Nine years after the establishment of the People's Republic of China, it was placed under the municipality of Shanghai in December 1958. Reclamation, particularly large-scale work on the island's northern and eastern tidal flats in the 1960s and ’90s, doubled the size of Chongming between 1950 and 2010. Dongtan was a proposed ecocity which was planned to open along with the 2010 World Expo in Shanghai but stalled following the 2006 ouster of Shanghai mayor Chen Liangyu.