environmental damage, and (b) the obligation of the State in which the environmental damage could originate to inform third States that could be affected in order to ensure cooperation to prevent the damage or, at least, to attenuate its severity, as established by articles 12 and 13 of the Convention for the Protection and Development of the Marine Environment of the Wider Caribbean Region. a) The obligation to make an environmental impact assessment 124. One of the pillars of international environmental law is the principle according to which States have the obligation to ensure that the activities carried out in their territory do not harm the environment and, consequently, individuals from other States, as emphasized by the International Court of Justice in its 1996 Advisory Opinion. 70 This principle of “due diligence” had already been recognized by arbitration case law in the case of Trail Smelter (Canada v. United States of America). 71 Furthermore, the International Court of Justice underscored its content in its judgment in the case concerning Pulp Mills on the River Uruguay (Argentina v. Uruguay), as follows: “The principle of prevention, as a customary rule, has its origins in the due diligence that is required of a State in its territory. It is “every State's obligation not to allow knowingly its territory to be used for acts contrary to the rights of other States” (Corfu Channel (United Kingdom v. Albania), Merits, Judgment, IC.J. Reports 1949, p. 22). A State is thus obliged to use all the means at its disposal in order to avoid activities which take place in its territory, or in any area under its jurisdiction, causing significant damage to the environment of another State. This Court has established that this obligation “is now part of the corpus of international law relating to the environment” (Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, IC.J. Reports 1996 (1), p. 242, para. 29).” 72 125. The obligation of prevention or due diligence recognized in general international law calls for the application of special measures aimed at preventing, or at least restricting, environmental damage. As the Arbitral Tribunal indicated in its decision of May 24, 2005, in the case of the Iron Rhine: “Today, both international and EC law require the integration of appropriate environmental measures in the design and implementation of economic development activities [...] where development may cause significant harm to the environment there is a duty to prevent, or at least mitigate, such harm. This duty, in the opinion of the Tribunal, has now become a principle of general international law.” 73 70 I.C.J., Legality of the threat or use of nuclear weapons, Advisory Opinion of July 8, 1996, pp. 241-242, paras. 29-30. 71 In this regard see: Trail Smelter case (United States, Canada), 16 April 1938 and 11 March 1941. UN III pp. 1905-1982. 72 I.C.J., Case concerning Pulp Mills on the River Uruguay (Argentina contra Uruguay), judgment of April 10, 2010, pp. 55-56, para. 101 73 Award in the Arbitration regarding the Iron Rhine (“Ijzeren Rijn”) between the Kingdom of Belgium and the Kingdom of the Netherlands, decision of 24 May 2005, UN Reports of International Arbitral Awards, Vol. XXVII, p. 35, para. 59 60