Women perform a fan dance as part of an exercise regimen at Hoan Kiem Lake in Ha Noi. Viet Nam is considered the second happiest country in the world, according to the 2012 Happy Planet Index. — VNS Photo Viet Thanh

HA NOI — Despite residents' constant groaning over traffic jams and overcrowded hospitals and schools, Viet Nam is considered the second happiest country in the world, behind Costa Rica, with Colombia third.

The ranking, the Happy Planet Index, was compiled and released by the New Economics Foundation, a UK independent think tank.

The Happy Planet Index ranks countries based on the health and happiness they produce per unit of environmental input, using global data on life expectancy, happiness and environmental sustainability.

Accordingly, Costa Rica, Viet Nam and Colombia live the longest, happiest, most sustainable lives.

The ranking this year marks a rise for Viet Nam compared to previous years. It ranked 12th and 5th in 2006 and in 2009, respectively.

Besides Viet Nam, the rest of the countries in the top 10 are from South America, including Belize, El Salvador, Jamaica, Panama, Nicaragua, Venezuela, and Guatemala.

The US ranks 105th and the UK ranks 41 on the index.

The lowest-ranked countries are Qatar, Chad and Botswana.

Saamah Abdallah, a senior researcher at the foundation, said rich and poor nations face different challenges but their ultimate goal is the same.

"The index not only reveals how far every country has to travel before it achieves good lives that don't cost the earth – or within its fair share of planetary resources – but also the direction it needs to move in," he said.

The independent think tank aims to improve quality of life by promoting innovative solutions to economic, environmental and social issues. — VNS