incident occurs. But the paragraph requires only that all 8tpracticable1U measures be taken, meaning those that are feasible, workable and reasonable, Further, only such measures as are “necessitated by the circumstances” need be taken, meaning those that are warranted by the factual situation of the emergency and its possible effect upon other States. Like paragraph 2, paragraph 3 foresees the possibility that there will be a competent international organisation, such 8’1 a joint commission, with which the watercourse State may co-operate in taking the requisite measures. And finally, co-operation with potentialiy af?-*ted States (again including non-watercourse States) is also provided for. Such co-operation may be especially appropriate in the case of contiguous watercourses or where a potentially affected State is in a position to render assistance on the territory of the watercourse State where the emergency originated. (5) m contains an obligation that is different in character from those contained in the two preceding paragraphs, in that it calls for 2..w See, e.g. article 11 of the Convention on the protection of the Rhine against chemical pollution, m, note 201, - 177 -anticipatory rather than responsive action, The need for the development of contingency plane for responding to possible emergenciee is 110~ well recogni zed. For example, ronmen t ‘1. (6) The obligation set forth in paragraph 4 is qualified by the word6 “when necessary”, in recognition of the fact that the circumstances of some watercourse States and international watercourse[s] [systems] may not justify the effort and expense that are involved in the development of contingency plans. Whether such plan6 would be neceesary would depenc¶, for example, upon whether the characteristics of the natural environment of the watercourse, and the use6 made of the watercourse and adjacent land areas, would indicate that it was po6sible for emergencies to arise. It is probable that with respect to
**Analysis**
The text discusses the measures to be taken in response to emergencies or incidents affecting international watercourses. It highlights the importance of taking feasible and reasonable measures, as well as co-operating with other states and international organizations. The focus is on preparedness and response to emergencies, rather than on the management of the watercourse itself. This suggests that the category is related to environmental protection and emergency response.

**Category**
Natural resources and environment, Humanitarian aid and relief