One recent morning, three figures in white lab coats descended cautiously into a pitch-black netherworld beneath a crumbling bridge in the Afghan capital. They picked their way through garbage and sprawled limbs, passing hundreds of huddled men whose gaunt, wary faces were briefly illuminated by the flare of matches and drug pipes.

The doctors were headed to a lone tent pitched nearby on the dry riverbed, where they knew that a female addict named Marzia had been sleeping on her own. They approached quietly, saying they had come to help. From within came shouts of “Go away, leave me alone!” Suddenly the young woman flung open the tent flap, cursing and hurling debris. Stumbling along the riverbed, she darted under the bridge and vanished into the protective company of fellow lost souls.

While rehab center staffers search for women in the dry bed of the Kabul River near a notorious addict colony under the Pule Sukhta bridge, plainclothes police destroy makeshift shelters at the site last month. This one was home to an addict, right, who is also an amputee. (Andrew Quilty/For The Washington Post)