Central to this is the city's badly maintained road system used by more than half-a-million vehicles, many of them old, polluting and unreliable.

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Green stormwater management is a collection of approaches that is dispersed across public and private land, and not a single system residing underground and maintained by one agency.

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Customers are better off if just one system is built and maintained, as long as the company that runs the system is prohibited by regulators from using its monopoly power to drive up prices.

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When most people think about open source, they usually think of the free Linux operating system, which is developed and maintained by a worldwide network of collaborators.

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While firms have built their own legal identifiers, but a single standard maintained by a third party would reduce costs and eliminate the need to translate the information from system to system, said another panelist.

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He maintained that costs would come down by improving the quality of care and the overall efficiency of the system.

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Mr Cameron also said it was important the UK maintained its system of funding and support for elite sports and praised the "very tough" conditions set by UK Sport - the organisation responsible for investing government money in Britain's top performers.

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