The subject-matter of this article is the Judgment of the International Court of Justice in the Gabčíkovo-Nagymaros case. Following an exposition of the relevant facts, it continues with a critical analysis of the Judgment of the Court. In addition to a brief analysis of the issues involving the law of treaties, the law of state responsibility, the law of state succession, and the treaty obligations of Hungary and Slovakia relating to the use of Danube water and the protection of its environment, it focuses on the rules and principles of general international law concerning the use of international watercourses and the protection of the environment that were applied by the Court in this case.

In a small note which Peter Kooijmans wrote to me in answer to a letter in which I congratulated him with his election as Judge in the International Court of Justice – the first Netherlands Judge in the Court after World War II apart from Professor Riphagen who only served as a Judge ad hoc in the Barcelona Traction, Light and Power Company Ltd. case – he stated that he considered himself to be a privileged man. Privileged, because the new position would allow him to continue to remain active in the field of international law considerably beyond the retirement age of 65 which applies to professors of international law and most other people in The Netherlands. Privileged, I would like to add, also in another respect. Very rarely it will be given to one person in his lifetime to fulfil so many different honourable positions in the field of international law and international relations at such a high level of responsibility as has been the case with Peter Kooijmans: Professor of public international law, United Nations Special Rapporteur on Torture, State Secretary (Staatssecretaris) for Foreign Affairs, in particular disarmament matters (1973–1977), Minister for Foreign Affairs and, finally, Judge in the International Court of Justice.

The present article deals with the fate of the 1976 Chlorides and Chemical Pollutants Conventions concluded by the riparian states of the Rhine and in the case of the latter Convention also by the EEC. It further analyzes the decision of 8 January 1979 taken by the District Court of Rotterdam in the case of certain Dutch horticulturists and the Dutch Stichting ‘Reinwater’ against the French Mines Domaniales de Potasse d'Alsace.

The author pleads that the Dutch Government institute proceedings against France before the I.C.J. considering the fact that the French Government refused to ratify the 1976 Chlorides Convention and the fact that the proceedings at present taking place before the Dutch Courts will not lead to a diminuition of the salt-load of the Rhine.

In the past few decades the quality of European rivers and lakes has deteriorated considerably as a result of the growth of population and the expansion of industrial and agricultural activities. Since pollution does not stop at State frontiers riparian States of international watercourses must cooperate in fighting it. In the course of time a number of European States have therefore agreed on treaty provisions to counteract the pollution of certain international rivers or lakes. The first of these provisions are to be found in certain fisheries agreements concluded at the end of the 19th century. Further, since the Second World War, treaties have been concluded especially for the purpose of abating pollution. However, these provisions and treaties –which have a limited geographic scope and vary in nature– have as yet not been very effective.

During the last century the use of water in Western Europe has increased enormously as the result of the growth of the population and the expansion of industrial and agricultural activities. At the same time and for the same reason the quality of the available fresh water resources has also rapidly deteriorated. The river Rhine in particular, once so often praised for its beauty, is nowadays, especially in its downstream sections, little more than an open sewer. This river has become seriously polluted with organic substances, chloride, heavy metals and other chemical pollutants. In recent years moreover a new form of pollution has made its appearance, namely the heating of the water through the discharge of cooling water by (nuclear) power stations. The heavy pollution of the Rhine not only affects the ecological balance but also other interests, such as the supply of drinking water, the use of the water for industrial purposes, agriculture, horticulture and recreation.