In this paper we establish a number of environmental indices to rate the green efficiency of cities in China, while at the same time using them to discuss two problems in China: emissions of sulfur dioxide (SO₂) and population distribution. The indices used in this paper have never been implemented in the literature. From them, we can understand the level of environmental protection in China and be better equipped to improve the country’s environmental pollution. We also use macroeconomic data in this paper, and draw valuable conclusions. The data cover 1998 to 2003. All nominal variables are transformed into real variables based on 1998 price levels using the GDP deflator. To the best of our knowledge, China’s eastern cities have the most prosperous economies in China. However, their overall green efficiency value is inferior to that of the central cities. We further find that no city has a population that exceeds the optimal population target value. This is an astonishing finding. The eastern cities’ emissions of SO₂ are the highest and their additional population capacity is the lowest. The overall performance of the central cities of China is therefore superior to that of the eastern cities. Finally, we also find that the development between the eastern and western areas of China is balanced.