However, the effectiveness of these kinds of schemes is still not clear, some arguing that they could provide perverse incentives. Revenues coming from environmental taxes, or at least part of them, can be reinvested for the environment. For example, in 1981 the National Assembly of Cuba approved the Law 81, also known as ‘Environmental Law', that allows the use of economic tools such as taxes for the development of activities that positively impact the environment (Whittle and Rey Santos 2006). They can be designed for general environmental or revenue raising issues (e.g. waste charges to help finance waste management collection and infrastructure), and also motivated specifically by marine litter considerations.