Almost everything medicine knows about the gut microbiome has been learned from Western cohorts - largely urban, largely European-ancestry populations eating a narrow band of diets. That makes the reference range for a 'normal' microbiome a Western reference range, and it is the range against which probiotics, faecal transplants and dietary interventions have been designed and tested. SAMBAR's contribution is a baseline drawn from healthy South Asians, which is what any clinical claim about an Indian patient's microbiome needs in order to be meaningful. The more pointed finding is that the ten communities did not converge as they urbanised: each followed its own trajectory, shaped by local culture, diet and geography. That undercuts the convenient assumption of a single 'urbanisation effect' on the gut and implies that a therapy calibrated on one population may simply not transfer to another. Given that diabetes, obesity and cardiovascular disease are rising fastest in exactly the populations that are urbanising fastest, the resource has an obvious downstream use - and it also carries an evolutionary reading, since community membership and geography turned out to track microbiome composition more closely than lifestyle labels did.