The temporal and geographic core of Jewish ritual purity was Second Temple Jerusalem. Like a nuclear reactor in which movements are carefully measured and protocols strictly enforced, the Temple operated according to stringent purity rules, including a gradated access system designed to keep away the tainted. Yet, purity was not only a Jerusalem syndrome. In the fields and orchards beyond the Holy City, many of the laws governing priestly tithes were aimed at protecting produce from contamination. Even non-priests formed eating clubs that let the purity punctilious in and kept the careless out. In fact, Second Temple sectarianism was fueled by debates about highly technical rules of purity. Some scholars have even speculated that the sectarians living in the caves around the Dead Sea abandoned Jerusalem because of the ritual challenges presented by urban plumbing. Recently recovered artifacts such as ritual baths and stone vessels (the latter were thought to prevent the spread of impurity) from archeological layers that postdate the destruction of Jerusalem in 70 C.E. show how the Jewish fixation on purity remained entrenched long after the Temple had been destroyed.
Shai Secunda, “Purity and Obscurity”, Jewish Review of Books (Summer 2017) [https://jewishreviewofbooks.com/articles/2661/purity_and_obscurity]