Chinese educational authorities will tighten scrutiny on Chinese-foreign joint education to address problems caused by for-profit, low-quality \"overseas study preparatory classes.\" Many Chinese senior high schools offer expensive \"international classes\" in cooperation with foreign educational institutions, many of them without approval from Chinese authorities, Sheng Jianxue, deputy director of the Ministry of Education\'s international cooperation and exchanges department, said at a press conference on Thursday. Only 90 senior high schools with Sino-foreign cooperative classes have been examined and approved by local authorities, he said. China allows Sino-foreign joint education programs in senior high schools, aimed at introducing new educational models and teaching methods, but such classes should be approved by educational authorities, Sheng said. However, China \"does not advocate\" joint education in the form of \"overseas study preparatory classes,\" according to Sheng. Schools established solely by foreign organizations in China are only allowed to enroll foreign students who legally reside in the country, Sheng added. Schools that meet criteria for Sino-foreign joint education should be approved by authorities, he said, adding that illegal schools should be \"absolutely clamped down.\" China currently has 1,979 approved Sino-foreign joint education projects, such as New York University Shanghai, China\'s first Sino-U.S. university jointly run by New York University and East China Normal University, and the Ningbo campus of Nottingham University in east China\'s Zhejiang Province, according to the ministry. Sino-foreign joint education has promoted China\'s school administration reform, increased educational opportunities, and opened China\'s education system to the outside world, Sheng said.