Period 3B and 3C deposits essentially cover the entire modeled area and represent the greatest extent of the ancient urban center.
J. M. Kenoyer has developed a model describing some of the processes that contribute to the urban growth at Harappa. Kenoyer's model is based on a shifting occupation during the several chronological periods at the site. Initial growth from a small site to a larger urban community occurred during Periods 1 and 2. Expansion of the settlement on Mound E occurred during the beginning of Period 3A. During later Period 3A, occupation either shifted or expanded to Mound AB. This shift apparently resulted in a lack of civic control resulting in refuse accumulation on Mound E. Kenoyer suggests that this shift may be from the development of new socio-economic groups and shifting power centers in Harappa. Renewal of Mound E occurred during Period 3B, possibly resulting in civic decay on Mound AB. Period 3C deposits show evidence of extensive congestion in all areas of the site and a lack of civil control.