To confront food insufficiency caused by the Great Leap Forward, China's central government promoted a national policy of 'agriculture as the priority'. The Shanghai municipal government launched a campaign to expand cultivated land within its jurisdiction by transforming wetlands on Chongming Island through a military-style campaign. Tens of thousands of urban workers were drafted into a Land Reclamation Army to meet national and municipal food self-sufficiency goals. Their campaign featured both attacks on nature and interpersonal abuse. In accordance with the central directives, wetlands totalling 8,000 hectares were drained for conversion into farmland. This conversion proved to be costly, as land with low fertility was created through the permanent destruction of the wetland ecosystem and reclamation workers suffered physical and psychological mistreatment. Although the transformation of wetlands was completed quickly, food production fell far short of targets. Furthermore, the land reclamation campaign imposed irrevocable costs on the island's established communities.