Az-zarqa', Jordan

The Zarqa River is the second largest tributary of the Jordan River, but that's little consolation when you're dealing with the heavy pollution and bureaucratic headaches that plague this industrial hub. With a basin area of 3,900 square kilometers, it encompasses the most densely populated region east of the Jordan, home to over 52% of Jordan's industrial plants. The water quality is so poor that the reservoir created by the King Talal Dam is unusable for drinking, relegated only to irrigation. Restoring this environmental "black spot" will cost a whopping $30 million, a price tag that highlights the challenges facing those who choose to settle in Az-zarqa'. Unless you're prepared to navigate persistent bureaucratic red tape and accept the foul odors of untreated sewage, this gritty city is best avoided.