Late Harappan refers to the post-urban phase of Harappan culture, which emerged after the decline of the urban phase of the Indus Valley Civilization. The Late Harappan period is marked by significant changes in settlement patterns, material culture, and economy. Here are the details:

Late Harappan Period:
- The Late Harappan period is estimated to have lasted from 1900 BCE to 1300 BCE, although the exact duration and chronology are debated among scholars.
- It is characterized by the emergence of smaller, rural settlements and a shift from the standardized urban planning of the earlier phase.
- The Late Harappan sites are often located near rivers or on the outskirts of the earlier urban centers.
- The material culture of the Late Harappan period shows regional variation and diversity, with a decline in the use of standardized weights, measures, and seals.
- The economy shifted from specialized craft production and long-distance trade to more self-sufficient agriculture and local exchange.

Causes of Decline:
- The causes of the decline of the Indus Valley Civilization and the emergence of the Late Harappan period are not clear, but several factors are proposed by scholars.
- Environmental factors such as climate change, natural disasters, and ecological degradation are suggested as possible causes of the decline.
- Internal factors such as social, political, and economic changes, including the emergence of regionalism and the breakdown of centralized authority, are also proposed.
- External factors such as invasions or migrations of Indo-European or other groups are suggested by some scholars.

Significance:
- The Late Harappan period is significant for understanding the transformation of the Indus Valley Civilization and the emergence of regional cultures and identities in South Asia.
- It provides evidence of the resilience and adaptability of the Harappan people in the face of changing environmental and social conditions.
- It also sheds light on the diversity and complexity of the post-urban societies that emerged in the subcontinent, laying the foundations for the later Vedic and early historic periods.