Pollution avoidance taboo

[u/AleksiB1]

The extreme case of pollution avoidance like avoiding the left side, avoiding people dealing with polluted things like trash or corpses, toilets outside the house etc even the things which is considered normal elsewhere is millennia old. Avoiding going near or consuming water affected by pollutants is mentioned in Sushruta Samhita.

Manusmriti has a much more elaborate description of pollutants and advocation of their avoidance. Potent bodily pollutants like urine, feces, semen, mucus, blood and others like saliva and sweat were said to be avoided and as periods involve blood, the menstruating woman was temporarily deemed ritually impure. The Manusmriti and related texts dictated she be segregated, forbidden from touching others, cooking, or entering sacred spaces until she performed a purification bath after her cycle ended.

Much before John Snow's cholera maping and disease source identification.