With Gurgaon developing as a major service sector and industrial hub, the Haryana government is mulling setting up a separate development authority for the Millennium City adjoining the national capital, a minister said on Wednesday.The Gurgaon Development Authority will be on the pattern of Delhi Development Authority and Greater Noida Development Authority, Haryana Public Works (Buildings and Roads) Minister Narbir Singh said here.Singh said Haryana Urban Development Authority, which is responsible for all sectors in all urban estates in Haryana, was unable to properly maintain the sectors in Gurgaon."More than 250 units of renowned multinational companies are operating in Gurgaon, where more than 120 sectors of HUDA have been carved out. Also, the number of sectors in Faridabad and other cities included in the National Capital Region have also increased significantly," he said, adding that the proposal was under consideration in view of the rapid urbanisation in the NCR, especially Gurgaon.