The “two mountains” theory, according to the State Council, was proposed by Chinese president Xi Jinping in 2005 during a trip to a village in Zhejiang province. (News website Hong Kong Free Press claims that the phrase had appeared in newspapers before it was popularised by Xi.) The full slogan is “clear waters and green mountains are as valuable as gold and silver mountains”, meaning that while economic development is a priority, the environment cannot be sacrificed for the sake of growth. It is also translated as “lucid waters and lush mountains are invaluable assets”. State news agency Xinhua says the theory “allows the world to understand ‘beautiful China’” and calls it a display of “Chinese knowledge and a Chinese solution” for global environmental problems. (For more, see Carbon Brief’s “Analysis: Nine key moments that changed China’s mind about climate change”.)