Gurugram, Aug. 29 -- After nearly three days of pumping out sewage, Gurugram Metropolitan Development Authority (GMDA) officials said on Friday that they have finally identified the source of a leak that caused a sinkhole to open at Iffco Chowk on the Delhi-Gurgaon Expressway. GMDA officials said they had started excavating the area around the damaged section of the sewer pipeline and would install steel-plate shuttering to prevent the road from caving in further. The replacement of the damaged pipeline and repair of the road are expected to take another five to six days, they said. The sinkhole formed on Tuesday afternoon after a portion of the sewage drain collapsed along the Iffco Chowk service lane from Delhi towards Jaipur, triggering panic among commuters and causing traffic congestion. Following the incident, two service lanes of the highway were barricaded, officials said. "There was heavy flow of sewage in the pipeline and despite us using five pumps to remove water from the pipeline since Tuesday evening, it took us almost three days to identify the exact source of the leak. The next step would be digging around the sinkhole to install shuttering so that the earth under the road does not cave in. It will take around five to six days to repair the stretch," said a senior GMDA official. Officials said that 20 metres of the damaged pipeline beneath the sinkhole will be replaced immediately. Another 100 metres of the pipeline towards MG Road will be upgraded using MWSL (machine wound spiral lining) technology to strengthen the line. The GMDA also plans to upgrade the entire sewer line between Iffco Chowk and Sikanderpur at an estimated cost of around Rs.9 crore, officials said. National Highways Authority of India (NHAI) officials, who are working with the GMDA on repairing the road, said they expected the work to be completed soon now that the source of the leak had been identified. "We are working to resolve the issue at the earliest," an NHAI official said....