means any substance which, if introduced into the sea, is likely to create a hazard to human health, harm living resources and marine life, damage amenities or interfere with other legitimate uses of the sea, and includes oil and any other substance subject to control by MARPOL 1973/78, and mixtures of such substances and water or any other substance;
[Definition inserted by section 27(c) of Act No. 23 of 1997]