Suresh Thakur dropped another batch of potato patties, known as batata vada, into the cooking oil that had been sizzling in a massive iron pan since early morning. He’d already shaped the patties, made with mashed potato mixed with masala spices, green chilli and, occasionally, finely chopped raw onion, into near perfect spheres, and dipped them quickly in a thick chickpea batter just before frying.