City clusters in China: air and surface water pollution

City clusters are made up of groups of large, nearly contiguous cities with many adjoining satellite cities and towns. Over the past two decades, such clusters have played a leading role in the economic growth of China, owing to their collective economic capacity and interdependency. However, the economic boom has led to a general decline in environmental quality. This paper will review the development and current status of the major environmental problems caused by city clusters, focusing on water and air pollution, and suggest possible strategies for solving these problems. Currently, deteriorating water quality is of major concern to the public and decision makers alike, and more than three-quarters of the urban population are exposed to air quality that does not meet the national ambient air quality standards of China. Furthermore, this pollution is characterized by high concentrations of both primary and secondary pollutants. Environmental pollution issues are therefore much more complex in China than in western countries. China is expected to quadruple its GDP by 2020 (using 2000 as the base year for comparison) and, consequently, will face even more serious environmental challenges. Improving energy efficiency and moderating the consumption of natural resources are essential if China is to achieve a balance between economic development and environmental health.