But it did say that the engine is 10 percent lighter than a 2.2-liter diesel engine currently sold in markets outside the U.S. and that it runs clean enough not to require complicated exhaust treatments to meet emissions regulations.

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However, in many parts of the world, water is not always clean enough for safe human use, or for sustaining healthy ecosystems.

UNESCO: MEDIA SERVICES

For one, clean energy investments have not had enough time to mature.

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The Earth does not have enough clean water, good pasture land or even livable space along coasts to have everyone in, say, the poorer areas of western China and central India living and driving the way we do in, say, northern Virginia.

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Nonetheless, critics say he has not done enough to clean up a problem-plagued force.

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The subliminal message from their questioning of key witnesses seems to be that they will recommend some pretty robust measures to clean up British banking - because they are not convinced that enough has been done after scandals over the mis-selling of Payment Protection Insurance (PPI) and interest swaps to address the problem of serious misconduct.

BBC: Week ahead in committees

Even if -- and I mentioned last night we have to increase production on oil, we have to increase production on natural gas, because we're not going to be able to get all our clean energy up and running quickly enough to meet all of our economic growth needs.

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