What Actually Happens Inside the Kidney
Your kidney filters roughly 200 litres of blood every day, pulling out waste and excess minerals and sending them out in urine. Most of those minerals stay dissolved. A stone begins when one of them stops dissolving and starts crystallising instead.The most common type is a calcium oxalate stone. When oxalate concentration in the urine rises, either because you're eating a lot of oxalate-rich foods, not drinking enough water, or absorbing oxalate unusually well in your gut, it binds with calcium and precipitates into crystals. Those crystals don't immediately become a stone. They cluster. Over days and weeks, more mineral layers deposit around the cluster until it becomes a hard, jagged mass large enough to block the ureter.A 2020 study published in the Clinical Journal of the American Society of Nephrology found that kidney stone prevalence in South Asia has been rising steadily, with India carrying a disproportionate burden, particularly in the so-called "stone belt" spanning Rajasthan, Gujarat, Maharashtra, and Punjab, where heat, hard water, and diet patterns converge. The study linked high ambient temperatures directly to concentrated urine and elevated stone risk.
