Tehran has a drug problem: Iranian crack addicts are finding their fix in steadily rising numbers. But the 'black crack' in Iran is made from heroin, not cocaine. With neighbouring Afghanistan and Pakistan still ranking as world leaders in the production of poppies and their derivatives, the flow of drugs into Iran has been hard to stem. Intent on documenting the plight of these addicts, Aslon Arfa struck out into the underbelly of modern Tehran, camera in tow, and compiled some devastating images. The results are raw and humanising, offering hope through exposure.