The re-emergence of towns and cities in the Ganga plain from around the 6th century BCE, the first major urban phase after the decline of the Harappan (Indus Valley) cities, hence called the Second Urbanisation.
- Occurred in the eastern and middle Gangetic valley, linked to the rise of the mahajanapadas and the use of iron tools that allowed clearing of dense forests and surplus agriculture.
- Marked by the spread of Northern Black Polished Ware (NBPW), the deluxe pottery of the period, and by punch-marked coins (early metallic currency).
- Growth of trade, crafts, and guilds (shrenis), and the appearance of large fortified cities such as Pataliputra, Rajagriha, Kaushambi, Vaishali, and Ujjain.
- Coincided with the rise of Buddhism and Jainism, which drew support from traders and the new urban classes that the Brahmanical ritual order disadvantaged.
- Distinguished from the First Urbanisation (the Harappan cities of about 2600 to 1900 BCE), which was centred on the Indus and Ghaggar-Hakra region.
The NBPW marker, punch-marked coins, the iron-agriculture-surplus link, and the contrast with the Harappan First Urbanisation are standard pointers for the post-Vedic period.
First Urbanisation (Harappan, Indus region) versus Second Urbanisation (Gangetic plain, 6th century BCE); NBPW belongs to the second, not the Harappan, phase.
Re-emergence of Gangetic cities around the 6th century BCE, marked by NBPW, punch-marked coins, iron, trade, and the rise of Buddhism and Jainism.