The construction work for Delhi Metro's Phase IV began on Monday at Haiderpur Badli Mor of Yellow Line, officials said. The work is part of first civil-contract awarded last month for the construction of a portion of the Janakpuri West RK Ashram Marg Corridor. The 28.92-km long Janakpuri West RK Ashram Marg corridor is an extension of Magenta Line and will come-up with 22-stations.