India, July 7 -- Artificial Intelligence (AI), clean energy, advanced electronics, defence systems--almost every technology defining this decade runs on rare metals, and demand is climbing fast. The market for them is projected to cross $21 billion by 2035, and a global scramble for supply is already under way. Yet digging these metals out of the ground is slow, costly and environmentally fraught. Which raises an awkward question: what if some of the richest deposits aren't underground at all, but piling up in our drawers, offices and scrapyards?

That is the golden opportunity hiding in e-waste. India is now the world's third-largest generator of electronic waste, behind only China and the US--which also makes it home to one of the plane...