A second serve: how used tennis balls come back to life

What if the thing you toss without thinking outlasts you by four centuries? That is the tennis-ball problem. Millions of them, every year, destined for centuries in a landfill. But in Qingdao, they have found a fix. The solution came from 20,000 dead balls reborn as a court you can actually play on. This is the story of waste that won't wait 400 years to disappear. / A viral complaint is sweeping…