Systematic scientific studies of malaria in China did not begin until the 1920s. The persistence of misconceptions about the disease and the absence of political stability, funds and trained personnel were obstacles to any large scale antimalarial campaigns. In the 1920s and 30s, antimalarial efforts involved epidemiologic studies, environmental alterations, and treatment of patients. During the Sino-Japanese War when the Chinese government relocated inland, China's antimalarial work focused on the control of the disease, especially in the western and southwestern provinces. After the founding of the People's Republic of China in 1949, nationwide antimalarial campaigns were initiated and enforced by the central government which also promoted intersectoral and interregional cooperation. Together with the building of a preventive and anti-epidemic infrastructure and health care system as well as the training of personnel, the government used techniques of mass mobilization to launch programs of vector control and mass therapy. Provinces were also organized into antimalarial regional alliances to facilitate malaria control and surveillance.