annual/maintenance of master sewerage scheme of sector 1 to 57, gurugram. removing of blockage and desilting of master sewer line of 1000mm i/d in palam vihar h. no. c/1-29 to krishna chowk (m.h no. 1 to m.h. no. 5), gurugram by high power super sucker mechanical device including cctv survey and all other works contingent thereto. .