This Preliminary Assessment was prepared by the United Nations Environment Programme (UNEP) in response to an official request from the State of Palestine for an assessment of the environmental impacts of the conflict in the Gaza Strip. The Preliminary Assessment provides a summary of what is known about the environmental impacts of the ongoing conflict in the Gaza Strip, including impacts on environmental management and waste disposal systems; energy, fuel and associated infrastructure; destruction of buildings and conflict-related debris; marine and terrestrial environments; and air quality. In addition to describing known, and in many cases visible, environmental impacts, this assessment highlights conflict-related environmental issues that are of serious concern, but about which the United Nations has limited information at this stage. Conflict was ongoing in Gaza throughout preparation of this report: the security situation and access restrictions prevailing in Gaza influenced the type of analysis UNEP was able to undertake. Some conflict-related impacts - such as the likely contamination of soil and the Coastal Aquifer by chemicals and heavy metals - can only be fully understood through more detailed sampling and analysis, which should be undertaken as soon as conditions permit.