China, India, Turkey and Arab partners provided about 13% of total official support for infrastructure through South-South development co-operation. Seeking to address inefficient and costly infrastructure delivery, many governments over the past two decades have turned to public-private partnerships (PPPs) to build and operate infrastructure. The key characteristic of PPPs is the outsourcing and "bundling" of project delivery components (e.g. design, building, financing, operations), to incentivise the builder-operator to incorporate long-term operating-cost considerations into the design and construction phases of a project, and to reduce co-ordination costs.