Housing demand and prices may rise in Noida as well as Greater Noida with the launch of a new metro rail service, linking the twin-cities in western Uttar Pradesh, according to real estate developers and consultants. The new metro rail service, called Aqua line, runs through 21 stations -- 15 of them in Noida and six in Greater Noida -- and covers a distance of 29.7 km. "The upgrading of infrastructure due to metro connectivity is expected to help in spurring the demand for residential units in the region.