Of course, the environmental Kuznets curve is a theory that needs to be supported or refuted with evidence, not a law of nature like the boiling point of water, and it's a theory that is under ongoing discussion and debate. And the experience of China, with its burgeoning economy and extraordinary environmental issues, is at the center of the debate. Dasgupta, Laplante, Wang, and Wheeler offer a summary of some possible outcomes in this diagram.
On the other side, optimists point out that countries which are currently industrializing can draw on the anti-pollution technology and legislative experience of other countries, and thus may be able to find ways to increase pollution by less than historical experience, and have the peak of the environmental Kuznets curve at a lower level of per capita income.
According to the World Bank, China's per capita GDP was $5,445 in 2011, so it is just reaching the levels where its pollution should first start to level off, and then to decline. Sam Hill has published a report called "Reforms for a Cleaner, Healthier Environment in China" as a working paper for the OECD economics department. It can be read for free on-line via a clunky browser here.
China's environmental problems have enormous costs. Hill writes (citations omitted): "Combined health costs from PM [particulate matter] and water pollution reached nearly 4% of GNI by the late 2000s. The cost of CO2 emissions ... together with material damage from air pollution and soil nutrient depletion, adds some 2.5% of GNI. Incorporating additional costs associated with energy and mineral depletion brings the total costs of environmental degradation to around 9% of GNI." With costs this high, even cold-blooded analysis by those who do not hug trees in their spare time will justify a greater degree of environmental protection.
Interestingly, there are signs that for some pollutants, the level of pollution is no longer rising with the growth of China's economy. For example, here's a figure about air pollution. The top line shows the growth of GDP. Emissions of sulfur dioxides and soot have not been rising with GDP, and even emissions of carbon dioxide have been lagging behind the rise in GDP in the last few years.
The policy prescription for reducing pollution in China is clear enough: close down older facilities, and make sure their replacements have up-to-date anti-pollution equipment; keep building sewage treatment facilities; put a price on polluting activities to encourage conservation; and so on. Sam Hill's paper has details.
But ultimately, China's path along the environmental Kuznets curve will be determined by politics and public pressure, and public pressure in China does seem to be building for stronger environmental protection. The (wonderfully named) Elizabeth C. Economy at the Council of Foreign Relations recently wrote a brief piece on "China’s Environmental Politics: A Game of Crisis Management," which notes the growing number of environmental public protests in China. In a society under such a high degree of government control, environmental protests can become a place where those discontented with government have a semi-safe space for dissent.