The statement by a supranational, national, or regional government of its approach to environmental protection. Pezzey (2004) Scand. J. Econ. 106, 2 contrasts environmental policy, ‘which internalises externalised environmental values’, with sustainability policy, ‘which achieves some form of intergenerational equity’. See C. Barrow (2005); try Tews et al. (2003) Eur. J. Pol. Res. 42, 4.