Sustainability is a concept used with increasing frequency in tourism development, planning and management circles. It is often linked to terms such as 'green' tourism and/or 'ecotourism'. C. Hunter suggested a number of other perspectives in which the environment is more, or less, central in concepts of sustainable tourism. Drawing on the work of E. Innskeep, a model of sustainable tourism can be created. This model can be represented as being: non-intrusive, non-depleting and renewable, scaled to the particular environment, natural in material makeup and presentation and well integrated into the local physical, social, cultural and economic environments. The environment has an intrinsic value that outweighs its value as a tourism asset. The tourism industry, local authorities and environmental agencies all have a duty to respect the guiding principles and to work together to achieve their practical realization in achieving sustainable tourism. The Economic Instruments involve use of taxes and charges which are intended to influence the behaviour of tourists.