"In the 1990s, there was a lot happening in property development in Australia. But even back then, I saw we could be doing more in terms of how we developed the urban landscape."

A frequent speaker around the country, Tan began to address audiences on urban development and green city development in particular.

In 2001 he joined Focus Capital, an investment property consultancy that seeks out the latest trends in global property development, where he is still a director. It also has other interests ranging from real estate and information technology to clean technology and renewable energy.

"At that time I started to think: 'Why develop one or two properties? Why not put together a framework that incorporates all aspects of urban development to help cities globally?'"

It was around this time that Tan's vision for Green World City began to take shape.

"I had this desire to create something - a framework if you like - that would have significant global impact and which could be adopted in cities around the world. That framework is for green cities ... cities that are socially, economically and environmentally pleasant places for people to live.

"Within a couple of years we had attracted a great deal of interest from all sorts of people worldwide, many of them leaders in their field and all sharing a desire to make cities better places to live."

In 2008, Tan decided to take the plunge and take Green World City global.

So what makes his organization any different from others already in the field?

"I would say it's our ability to bring people together and work within a framework to solve a particular problem, whether it's how to make cities environmentally friendly or improve the urban transport system," Tan says.

It wasn't long before the United Nations picked up on what Green World City was doing and asked Tan to join the steering committee of UN-Habitat, which is dedicated to promoting socially and environmentally sustainable human settlement developments and the achievement of adequate shelter for all.

Although he is the principal founder of Green World City, Tan does not take all the credit, and is quick to point out that the organization is supported by many talented people globally working to develop programs for sustainable city development.

As the organization's message began to spread, it found much interest from all corners of the globe in developing green sustainable cities.

"As we become an increasingly urbanized planet, people want their environment pollution-free so they can breathe easily and have green spaces to walk and relax. They also want urban transport systems that are clean and efficient," he says.

Tan says his organization has advised more than 120 city governments to make those green living dreams a reality, and that the process is a relatively simple one.

"We set up a framework, show them our success stories and (tell them) how they can achieve the same results.

"That is what they want to know - how can I achieve the same results for my city?"

Tan has met with most of the region's top decision makers, from prime ministers and presidents down to city planners.

In China, for instance, Green World City has advised more than 50 cities on eco-friendly urban development.

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