- E.J.H. Mackay and Mortimer Wheeler were early archaeologists who proposed theories involving diffusion of either people (Mackay) or the 'idea' of civilization (Wheeler) from Mesopotamia (West Asia) to explain the origins of the Harappan civilization, citing similarities in urban features, seals, etc. - Amalananda Ghosh's extensive exploration in the Ghaggar-Hakra region led him to propose that the Harappan civilization evolved indigenously from the preceding pre-Harappan cultures found in the same region. - M. Rafique Mughal, through his detailed work on the distribution and nature of early Indus sites, further strengthened the indigenous origin theory. He emphasized the developmental stages within the Indus Valley itself and argued against significant external stimulus or inspiration from Mesopotamia for the formation of the mature Harappan civilization. He highlighted the unique trajectory and local roots of the Harappan culture.