A new report examining the environmental impact of Asia’s fastest growing metropolises has identified a tipping point in average wealth that triggers the cities’ inhabitants to consume less water and generate less waste and carbon dioxide emissions (CO2).

The emergence of a growing middle class across Asia has been the subject of intense debate in environmental circles, with experts warning that the increasing wealth of countries such as China and India could trigger huge environmental damage if resource-intensive consumption patterns established in the West are precisely replicated by developing countries.

However, the Asian Green City Index, published today by Siemens and the Economist Intelligence Unit (EIU), found that richer Asian cities consistently performed better than poorer cities, suggesting that higher income does not necessarily mean higher resource consumption.

The report ranks 22 Asian cities based on their environmental performance and policies in eight categories: energy and CO2, land use and buildings, transport, waste, water, sanitation, air quality and environmental governance.

In contrast to a similar study carried out in Latin America last year, the EIU found a strong link between GDP and environmental performance. Asian cities had a steady rise in resource consumption up to about $15,000 (£9,363) per capita GDP, but consumption declined after about $20,000.

The six cities in the top income bracket – above £29,000 GDP per capita – consistently used less water, and produced less waste and fewer carbon emissions than the five cities in the mid-range GDP bracket, with a per capita GCP between US$10,000 and US$25,000.

Singapore was dubbed the greenest city, partly as a result of the government’s historical focus on sustainability since it won independence in 1965. Additionally, Singapore residents were the fourth-wealthiest among the 22 cities measured, generating a GDP per person of $36,500.

Jan Friederich, research head of the EIU study said the results showed “very clearly” that higher income does not necessarily equate to higher resource consumption.

“In the prosperous Asian cities, environmental awareness is greater and infrastructures are more efficient,” he said. “These cities are actively cutting their consumption of natural resources and are thus developing more sustainably. In addition, cities that performed well are characterised by their ability to successfully implement environmental projects and consistently enforce regulations.”

Dr Hyun Bang Shin, urban geography lecturer at the London School of Economics said that in China there is a link between increased income and environmental awareness. “As wealth grows many of the new middle class are becoming much more aware of environmental issues,” he said “They seem to be exerting pressure on local governments, [but] whether or not the interest in environmental protection expands beyond their immediate neighbourhoods and surroundings remains to be seen.”

Overall, the study found that the average annual CO2 emissions per capita in Asian cities was 4.6 tons, less than the corresponding figure for Europe of 5.2 tons per capita a year.

Similarly, the 22 Asian cities produced an average of 375 kilograms of waste per capita and year, less than in Latin America where each person accounts for an average 465 kilograms of waste and Europe, where average waste levels reach 511 kilograms.

Nevertheless, Asia’s cities still face challenges in meeting environmental targets, not least the fact that all of the cities studied breached World Health Organisation Standards for air pollution levels.

Cities were also urged to boost renewable energy supplies, which accounted for 11 per cent of the total electricity generated on average. By comparison, the average in Latin America was 64 per cent due to the high proportion of hydroelectric power plants.

Even Singapore’s CO2 emissions exceeded the limit required to prevent a rise of global temperatures by two degrees, said Siemens chief sustainability officer Barbara Kux.

“The rapidly growing cities in Asia simply don’t have the time to develop slowly over centuries, as did European cities,” she told reporters today. “To meet and master the challenges of the future, Asia’s cities must ‘leapfrog’ in their development.”