YINCHUAN, Sept. 6 (Xinhua) -- China has spent nearly 1 trillion yuan (146 billion U.S. dollars) on ecological conservation and environmental protection over the past decade, a senior official told an international seminar on ecological compensation held Sunday in northwest China.

    Of the total investment, more than 700 billion yuan went to projects to reforest cultivated land, return grazing land to protected grassland, protect natural forests and conserve river sources on the Qinghai-Tibet plateau and for the south-to-north water diversion program, according to Du Ying, vice minister of the National Development and Reform Commission.

    Another 200 billion yuan was used for pollution control in major river valleys and urban sewage treatment projects, Du said at the seminar that was held in Shizuishan city of northwest China's Ningxia Hui Autonomous Region.

    The seminar was jointly sponsored by the National Development and Reform Commission, the Ministry of Environmental Protection, Asian Development Bank and the government of Ningxia Hui Autonomous Region.

    The seminar attracted nearly 100 participants from more than a dozen countries and regions, including the United States, Germany and Australia.