China spent 29.57 billion yuan (about 4.43 billion U.S. dollars) to restore grassland from grazing land over the past 15 years in a move to protect the environment, the National Forestry and Grassland Administration said Tuesday.

During that period, the project created 830 million tonnes of fresh grass, the equivalent of the grass yield produced by prairies in five Inner Mongolias, the administration said.

In 2017, China's fresh grass yield was 1.065 billion tonnes, an increase of 2.53 percent from a year earlier, marking the seventh consecutive year with total fresh grass yield exceeding 1 billion tonnes.

"Although remarkable improvement has been made in the country's grassland ecological environment, critical contradictions exist between ecological conservation and regional economic development," said Liu Jiawen, deputy director of the grassland monitoring center of the administration. "In the next move, efforts should be made to step up the proper use of grassland to prevent it from unauthorized occupation and improve efficiency."

China has 392.8 million hectares of grassland, 12 percent of the world's total.