Environmental law is a new, rapidly evolving, and increasingly important area of jurisprudence. Although various industrialising countries introduced environmental controls in the nineteenth century, environmental law only began to emerge as a discrete subject in the late nineteen-sixties. In North America and Europe, early environmental law tended to follow the traditional “command and control” approach. This form of regulation is sometimes said to be “top-down”. It is based on a state-centred vision of environmental protection. A government will typically establish performance standards for polluters and allow them to buy licences. Polluters who fail to comply with the conditions specified in their licences may be prosecuted or face civil actions.