The Australian photographer Andrew Quilty has been documenting war-ravaged Afghanistan since December 2013. His arrival coincided with the planned withdrawal of Nato forces; what followed should have been a period of ‘resolute support’ and rebuilding. Instead he has witnessed the resurgence of extremist groups, mass displacement of families and the traumas of war. This month Quilty became the first photographer to win the Gold Walkley for excellence in Australian journalism. Guardian Australia invited him to present a retrospective of his work