The world today stands at a threshold of serious environmental crisis. The rising population of the developing countries and the affluent consumption and production standards of the developed nations have put a huge stress on the environment in terms of its functions of supplying resources and assimilating wastes. Many resources are becoming extinct since their use is beyond the carrying capacity of the environment, leading to an environmental crisis.
In earlier times, the demand for environmental resources and services was much less than their supply. Recently increased demand for goods and services has led to advanced industrialisation. This has caused pollution which is more than the absorptive capacity of the environment. The rate at which the resources are extracted by man has been more than the rate of regeneration of the resources, causing serious environmental problems. The demand for resources for both production and consumption has gone beyond the rate of regeneration of the resources increasing the pressure on the absorptive capacity of the environment.