[4][5][6] The diagnostic artifact and namesake of this culture is the Northern Black Polished Ware, a luxury style of burnished pottery used by elites.
This period is associated with the emergence of Indian subcontinent's first large cities since the decline of the Indus Valley civilization; this re-urbanization was accompanied by massive embankments and fortifications, significant population growth, increased social stratification, wide-ranging trade networks, specialized craft industries (e.g., carving of ivory, conch shells, and semi-precious stones), a system of weights, punch-marked coins, and writing (in the form of Brahmi and Kharosthi scripts, including inscribed stamp seals).
[10] However, the same cities continued to be inhabited, and the period from c. 200 BCE – c. 300 CE was still "marked by urban prosperity all over the subcontinent," corresponding to the Shunga and Satavahana Dynasties, and the Kushan Empire.
[citation needed] Sites in Sri Lanka such as Anuradhapura have also yielded Northern Black polished ware during the period 500 BC-250 BC indicating interaction with the gangetic valley.
[7] Samuel, Geoffrey (2010), The Origins of Yoga and Tantra: Indic Religions to the Thirteenth Century, Cambridge University Press