INDIAN GEOGRAPHY

Detailed explanation-1: -Elevated metro system is a rapid transit railway with tracks above the street level via ducts or other elevated structures. On the other hand underground metro, as the name suggests the tracks are below the ground surface.

Detailed explanation-2: -subway, also called underground, tube, or métro, underground railway system used to transport large numbers of passengers within urban and suburban areas. Subways are usually built under city streets for ease of construction, but they may take shortcuts and sometimes must pass under rivers.

Detailed explanation-3: -Despite the advantages of an underground metro, cities across the world have a mix of underground, over-ground and elevated tracks. Apart from the lower cost of construction, elevated lines require less electricity for cooling and lighting. Cities across the world have a preference for elevated MRTs.