The boy hopped in the snowed-in family car to warm up, but the engine was running and the exhaust pipe was blocked by snow, causing carbon monoxide to accumulate in the car.

CNN: STORY HIGHLIGHTS

Part of a main road has collapsed in Surrey leaving a car submerged in water after a mains pipe burst.

BBC: Woking A320 collapses after Veolia water mains burst

Run a car on hydrogen and pure water drips out the tail pipe.

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The car doesn't need the carbon dioxide to run, so it sends it out the tail pipe and into the atmosphere.

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