The second Global Young Scientists Summit in Singapore was officially closed on Friday by President Tony Tan Keng Yam, who also announced the winner of the summit's Singapore Challenge to come up with ideas for sustainable cities.

Mr Yossi Kabessa, a researcher at the Hebrew University of Jerusalem in Israel, won a gold medallion and US$100,000 ($128,130) for his water monitoring proposal. This uses genetically-engineered bacteria, airborne vehicles and fast-response teams to detect and contain pollutants and other harmful substances in the water supply system.

Infocomm Development Authority executive deputy chairman Steve Leonard, who led the challenge's seven-strong judging panel, said it would contact other agencies here such as national water agency PUB to see how Mr Kabessa's idea could be used here.

The five-day summit was organised by the National Research Foundation and attended by 350 young researchers. There were 18 science and technology speakers, 13 of whom were Nobel laureates. Most of the other participants were post-doctoral fellows and PhD students nominated by top academic and research institutions such as the University of Cambridge.

President Tan said in his closing speech that Singapore can help find scientific solutions to problems that affect people and cities around the world, such as threats to energy, water and food supply, ageing population, infectious disease outbreaks and the impact of climate change. "Cities can make life more efficient, but if not well managed, they could equally cause distress through inadequate infrastructure and sanitation, economic instability and cultural tension," he said.

Those competing in the Singapore Challenge had to present ideas on how technology could be used to build sustainable cities. Thirty-five proposals were submitted and 10 short-listed, including a real-time transport management system to match demand and supply, and remote sensors to help people keep track of elderly relatives who are at home alone.

Mr Leonard said Mr Kabessa's water monitoring idea stood out because "it would be helpful to Singapore and important for other countries around the world". He added that all of the 10 finalists' submissions would be considered by the relevant government agencies here.