New York Times: When residents of this northern Chinese city hang their clothes out to dry, the black fallout from nearby Handan Iron and Steel often sends them back to the wash. Half a world away, neighbors of ThyssenKrupp’s former steel mill in the Ruhr Valley of Germany once had a similar problem. The white shirts men wore to church on Sundays turned gray by the time they got home. These two steel towns have an unusual kinship, spanning 5,000 miles and a decade of economic upheaval. They …