Rae Kwon Chung, an Escap expert on environment and urban development, said the so-called social-asset cost in Thailand in the past few years had become proportionately five to 10 times higher than in countries like United States, Japan and the United Kingdom.

To reduce the cost, Thailand must improve its public transport system and traffic management to encourage motorists to drive less. Better conditions would also help increase the quality of life for Bangkok residents, he said.

Chung also proposed an Escap development guideline for Thailand that focuses on ecological and environmental improvements - a solution he said would lead to a slow-paced but increasingly solid economy and eventual prosperity.

The guideline, known as the Green Plan, has been widely adopted in developed countries. He said countries in the Asia-Pacific region had more green areas than Japan and the US, but their domestic ecological value indexes were lower than those of some African countries.

The seminar, titled "Gross National Happiness (GNH) of the Countries in the Mekong River Basin", is a regular event in which eight local and regional NGOs participate. The next session will be held here either next month or in October.

Singye Dorji, Bhutanese ambassador to Thailand, said his country's king placed importance on increasing GNH rather than on Gross Domestic Product.

Social critic Sulak Sivalak said Thailand and Bhutan were similar a hundred years ago, but Thailand had made the mistake of accepting Western civilisation, which focused more on material possessions rather than traditional spiritual values.

Sulak said Bhutan was now formulating a new development doctrine based on Buddhist principles that had drawn interest from NGOs in the six countries bordering the Mekong River, including Thailand.

Karma Ura, a Bhutanese official responsible for drawing up the country's national development plans, said the GNH-based development model could potentially lead to a happy, peaceful and knowledge-based society.