UJJAIN is comprised of fertile high mesas surrounded by even more lush jungles in the valleys below.  Populations are well-established in the uplands, but the jungles are unfortunately dominated by thorny vegetation called "dardbelen".  This plant secretes an oily substance that is intensely painful to touch, and potentially lethal if enough is absorbed into the bloodstream.  There are no heavy industries on Ujjain, and efforts to clear away the dardbelen with tools or fire have proven counterproductive.  Dardbelen is always the first thing that grows back, usually in thicker concentrations without other competition.  Ujjani have unanimously agreed not to attempt poisoning the land, for fear of causing an even worse catastrophe.  So they live in their safe high settlements where the dardbelen does not reach, and communication between mesas is uncommon.  Once in a great while someone will make the arduous journey, though.  They are invariably treated as brave heroes by their new homelands, for none ever choose to return to their place of origin.