Around five to six auto rickshaws parked in a workshop were buried in the debris when a portion of outer wall of Pacca Qilla caved in near Goods Naka side here on Monday noon. The auto rickshaws were parked inside the workshop when a 20 to 25 feet portion of the outer wall of the fort started sliding and caved in, an eye witness informed, adding that the auto rickshaws were buried in the debris, however, the employees of the workshop escaped unhurt. However, no casualty was reported, the police confirmed.