Even in war, Mehrab Ahmadzai waits for rain. The 48-year-old farmer is from Surkhrod district, in Afghanistan’s eastern Nangarhar province near the border with Pakistan. When the latest hostilities between the two nations arrived in late February, the district was among those caught in the cross-fire. Yet, when Ahmadzai looks to the sky, the prayer he offers up is for water. His wheat is rain fed....