Infrastructure projects – including ports, pipelines, hospitals, highways, and water, sewage and phone systems – provide the bedrock of national prosperity and well-being. They facilitate transport, promote communication, provide energy and water, boost the health and education of the workforce and enable the whole economy to flourish. The costs of building infrastructure are vast, but the costs of failing to make such investments are incalculable. Improved infrastructure produces abundant benefits for the economy, environment and social progress. However, many countries, developing and developed, are facing significant infrastructure deficits, owing to growing populations, urbanization, changing demands and ageing assets. The strong demand for infrastructure and its insufficient provision imply a global investment gap of about US$1 trillion yearly through 2020. The development of environmentally clean infrastructure would raise this estimate by an additional US$200-US$300 million yearly.