LONDON - Protecting the environment makes nations more prosperous, a think tank said on Thursday, as a study showed Slovenia is the country best at using nature to improve the well-being of its citizens.

In its study, the London-based Legatum Institute for the first time included governments' efforts to reduce pollution, preserve biodiversity and limit the exploitation of natural resources in a formula to calculate its annual prosperity index.

"Protecting the environment, leaving citizens with a nicer, cleaner and even prettier environment, is strongly linked to well-being," Alexandra Mousavizadeh, director at the Legatum Institute, told Reuters.

The index is published amid increased global efforts to tackle climate change and foster sustainable growth.

In September last year, U.N. member states set a number of ambitious targets to end poverty, protect the planet, and ensure prosperity for all by 2030.

In December, nearly 200 nations agreed to keep global temperature increases to below 2 degrees Celsius to curb global warming, as part of the landmark accord reached in Paris.

The Legatum Institute's index measures the prosperity of 149 countries based not only on their wealth but also on a series of other factors including education, personal freedoms, how safe people feel and how they get on with their neighbors.

In 2016, New Zealand was ranked first, followed by Norway, while Slovenia came top in the category dedicated to the natural environment.

Its ranking was due to the "aggressive" environmental policy Slovenia has adopted over the past decade, which has included the creation of large protected areas on land and sea, according to the institute.

"Slovenia is a country with a high diversity of natural environment gathered in a small area," the Slovenian ministry of the environment said in a statement. "Preserved nature is our core national treasure and our identity."

The creation of natural parks increased health and happiness as well as helping the tourism industry, which, in turn, boosted the country's overall wealth, said Harriet Maltby, head of policy research at the institute's Prosperity Index.

The new index penalized fast-developing countries like China and India that generated high levels of growth, reducing poverty, but at the expense of air quality.