Pollution-free vegetables thrive in north China's Hebei

A farmer works in a greenhouse of pollution-free vegetables in Sanhe city, north China's Hebei province, March 19, 2014. The annual output of pollution-free vegetables in Sanhe reached 800,000 tons with the value up to 1.5 billion yuan (about 241.8 million U.S. dollars). [Photo/Xinhua]