The Swiss-based Holcim Foundation wants to "inspire a built environment that goes beyond convention to address the challenges of sustainability", the foundation said in a statement.

The Swiss Federal Institute of Technology, Massachusetts Institute of Technology (MIT), Tongji University of Shanghai, Universidad Iberoamericana of Mexico City and the University of the Witwatersrand of Johannesburg support the awards.

It is the second awards, with the first in 2005 and 2006 attracting more than 3,000 submissions from 120 countries.

Joint winners of the main award were an urban-integration project in Caracas, Venezuela, and a design for a new railway station for Stuttgart, Germany. The runners-up were a regional master plan and renewal strategy for the Mulini Valley near Amalfi, Italy, and a low-cost housing and urban-renewal project in Montreal, Canada.

The competition showcases sustainable responses to technological, environmental, socio-economic and cultural issues affecting contemporary building and construction. Any involvement in the area of sustainable construction is eligible - architects, planners, engineers or project owners. All building projects are eligible if construction did not start before June 1 this year.

The first phase of the competition selects regional winners that will automatically qualify for the global competition in 2009.

In addition to projects at an advanced stage of design, the competition has a special category for concepts. It is open to professionals younger than 35.

The regional juries are headed by architect and author Harry Gugger of Switzerland, architecture deans Adele Naude Santos and Luis Cortes of MIT and Universidad Iberoamericana respectively and architects Joe Addo of Ghana and Ashok Lall of India.

Indian architect Charles Correa chairs the global jury panel. More information can be found at holcimawards.org.