What factors have been suggested as possible explanations for the changes in the Harappan civilization?

All of the above

Several explanations have been proposed for these changes, including climatic shifts, deforestation, floods, and alterations in river courses. While some of these factors may have affected specific settlements, they fail to account for the collapse of the entire civilization. It is apparent that a unifying element, possibly the Harappan state, came to an end. This is evidenced by the disappearance of seals, script, distinctive beads, and standardized weight system, and the decline and abandonment of cities. The development of new cities in a completely different region would take more than a millennium to occur on the subcontinent.