How is the city of Aramanth described in the novel, The Wind Singer?

Originally a small salt-mining camp, Aramanth is described as a wealthy, prosperous, and powerful city. A city of megalithic proportions, it is designed in concentric circles. The closer in the circle one lives, the wealthier and more powerful one is, without the outermost circles being for the poorest and least privileged. Aramanth is ruled by a Board of Examiners who rate citizens based on their ability to perform in tests. The city is presumably ruled by Emperor Creoth the Sixth, who doesn't seem to have too much power, except to continually veto all attempts to tear down the wind singer tower at the heart of the city.