[en] In the event of a severe nuclear accident releasing radioactive materials to the atmosphere, there is a potential for widespread contamination of both the urban and rural environments. In some instances of environmental contamination, natural processes may eventually reduce or eliminate the problem without man's intervention. The situation with respect to radioactive contamination is no different except that radioactive contamination will also disappear through normal physical radioactive decay. In other cases, man is often able to mitigate potential harmful effects by cleaning, washing, abrading or by the application of chemicals. The actions taken by man to mitigate the potential harmful effects of contamination are described as countermeasures. In the case of radioactive contamination, the objective of countermeasures is to minimise radiation doses to man. This document is intended as a guide to those groups who may, at very short notice, be called upon to manage and reclaim radioactively contaminated urban and rural environments in the Nordic countries. However, much of the information and recommendations are also equally applicable in other countries. The document is divided into eight distinct parts, namely: 1. The Urban Environment; 2. The Cultivated Agricultural Environment; 3. Animals; 4. Forests; 5. Freshwater and Fish; 6. Management and Disposal of Radioactive Waste from Clean-up Operations; 7. Radiation Protection and Safety of Clean-up Operators; 8. Resources Available in Society. (EG)