Its not water, but Li Bing developed a process for extracting this commodity from wells. Huo Guang initiated a series of debates, or "discourses," about a Han Dynasty monopoly on iron and this commodity. The Great Hedge of India was planted along the Inland Customs Line to facilitate the collection 
Its not water, but Li Bing developed a process for extracting this commodity from wells. Huo Guang initiated a series of debates, or "discourses," about a Han Dynasty monopoly on iron and this commodity. The Great Hedge of India was planted along the Inland Customs Line to facilitate the collection of a tax on this good. A nonviolent protest was planned for a center of this commodity's production at Dharasana, but its leader was arrested a month after he arrived in Dandi. For 10 points, name this good whose taxation was protested by a Mohandas Gandhi march.