The water dispute driving the turbulent relationship between Afghanistan and Iran is in an area faced with worsening climate change. The waters of the Helmand river are a lifeline for border communities, and a live wire that has at times nearly sparked wars. We follow the twists and turns of the row between Kabul and Tehran, and the shifting role of the Taliban within it. Presenter: Krassi Twigg Producer: Kriszta Satori