In 2001, excavation of perimeter wall  was extended to the Northwest. Here the surface of the wall is being cleared and the bricks outlined. Note the excavation in the foreground left where there was no mud-brick.
Ancient Indus walls.
Cross-sections inside (top) and outside (bottom) of perimeter wall . The wall itself, being of mud-brick, was heavily eroded, sometimes to a lower elevation than the adjoining more densely packed street debris.
Ashy debris deposits continued to accumulate outside of the perimeter wall, covering the curtain wall. These date to the end of Harappa Period 3B and the beginning of Period 3C.
Deposits of building debris and household rubbish were discarded over the perimeter wall into the open area below and were retained by the curtain wall.
The Trench 11 area showing the perimeter wall (on the left), the curtain wall, and the Period 3C drain that cut deeply into the Period 3B deposits (see the labeled plan in 72). The sediments outside of the perimeter wall are hard packed ashy debris
Workmen are cleaning the Trench 11 area in preparation for photography during the 1997 excavation season. Perimeter wall  is on the left.
The reconstructed brick wall is covered each year with a protective coating of clay and straw plaster. The original structure and unexcavated levels remain safely buried beneath a layer of bricks and back dirt.
The brick wall may have been the foundation for a wooden superstructure and the white tags show where wooden posts were fixed. The doorway and threshold are located on the right side of the photograph above the scale.
North end of Harappa Mound AB, looking down on the Kot Diji phase levels from the heights above the Harappa phase baked brick wall (on the right) that has been covered with protective plaster for conservation.