Singapore's low water- and air-pollution levels and efficient energy and transportation systems made it the second greenest country. However, more renewable energy sources were needed.
Australia and South Korea tied third, with Australia having low water pollution. Australia also ranked highly due to its low air pollution, while South Korea had significant green space and an efficient train system.
"While these countries are clearly leaders of positive environmental impact in the region, both could do more to reduce their greenhouse gas emissions," Hofmann said.
New Zealand ranked best for air quality and green space, but ranked second to last for plastic consumption.
"... New Zealand would do well to reduce its consumption of plastic - the country averaged the second most daily plastic waste per capita (0.3kg) of those in our study."
At the end of last year, Associate Minister for the Environment Eugenie Sage confirmed single-use plastic shopping bags would be banned in New Zealand by July 2019.
New Zealand has also signed up to the New Plastics Economy Global Commitment – a global pledge to address the root causes of plastic pollution.
