The cloth is placed in a steaming box to fix the dye with heat and moisture, and afterward rinsed in water to remove paste and excess dye. This step, known as yūzen nagashi (flowing yūzen), was formerly done in the main rivers of Kyoto: Kamo, Hori, Katsura, Shirakawa, and Kamiya. The river would change color, depending on the hue of the dye used. Mounting environmental awareness led to the Water Pollution Control Act of 1970. Washing of dyed textiles is no longer done in the river, but in workshops using artificial waterways.