Riddle Me This

Why is there a street cleaner cleaning the sidewalks, with full spraying water, when it is pouring rain??
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> Water trucks regularly spray our road at least twice if not three times a day. Why? Because if they think it helps control the dirt and dust, it doesn't. And where do they get the water? Seems like such a waste.
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> There are some things I will just never understand in this country. You can count this as one.
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