Oubei Twin Towers Robin Farmers' Market. Yongjia is a city, and the largest vegetable market in Oubei is Robin Farmers' Market, covering an area of 500 mu. Yongjia, a county under the jurisdiction of Wenzhou City, Zhejiang Province, China, is located in the southeast of Zhejiang Province, on the north bank of the lower reaches of Oujiang River, with Yueqing and Huangyan in the east, Qingtian and Jinyun in the west, Xianju in the north and Wenzhou across the river in the south.