ae meaning that joint, co-operative action is to be takea -vfhere appropriate, and that such action is to be taken on an equitable basis. For example, joint action would ueually be appropriate in the case of contiguous watercourses cr those being managea and developed a8 a unit. What constitutes action on an l!w The following observation contained in the Proposed Medium-Term Plan is relevant in this connrctionl “The maintenance of biological diversity, which encompasses all species of plants, animals and micro-orgonieme and the ecoeysteme of which they are part, is a major element in echieving sustainable development.” -a, note 148, pare. 16.7. l!Li/ Article 6, para. 2. - 150 -equitable basis will, of courser vary with the circumstance@, J&I/ Among the factors to be taken into account in this (jnnectior_ are the extent to which tha watercourse States concerned havo contributed to the problem and the extent to which they will benefit from its solution. Of course, tho duty to participate equitably in the protection and preservation of the ecosystems of an international watercourse [system] is not to ba regarded ea implying an obligation to repair or tolerate harm that has resulted from another watercourse State’s breach of its obligations under the draft articles. m/ Rut the general obligstion of equitable participation demands that the contribut.ions of watercourse States to joint protection an11 preservation efforts be at least proportional to the measure in which they have contributed to the threat or harm to the ecosystems in question. Finally, it will be reculled that article 194 of the 1982 Unitod Nations Convention on the Law of the Sea also requires that measurec be taken “individually or jointly”, in that ca8e with regard to pollution of the marine environment, m/ This provision reflects a recognition that joint protective act;ion may be nececsary
**Analysis**
The text discusses the concept of joint action and equitable participation in the protection and preservation of international watercourses and their ecosystems. The language used is technical and focuses on the legal framework and obligations of watercourse States. The text also references international agreements, such as the 1982 United Nations Convention on the Law of the Sea, which suggests a focus on international cooperation and environmental protection.

**Category**
Natural resources and environment, International trade