Technical Note from a scoping mission to Mosul, Iraq, to analyse the environmental impact of areas retaken from ISIL. During his visit to Iraq in May 2017, Erik Solheim responded positively to the government’s request for support in conducting an assessment of the environmental impacts in areas formerly occupied by ISIL (so-called Islamic State in Iraq and the Levant, alias Daesh). The Head of UN Environment witnessed first-hand the devastating environmental impacts affecting the inhabitants of Qayarrah town, 60 kilometres south of Mosul, from oil wells deliberately set on fire. ISIL’s scorched earth tactics provide a dramatic illustration of how pollution from conflicts and deliberate sabotage and looting of industrial facilities and civil infrastructure can affect people’s health and livelihoods for decades, and impede reconstruction and peacebuilding efforts.