The Delhi Metro is a rapid transit system that serves Delhi and the adjoining satellite cities of Faridabad, Gurugram, Ghaziabad, Noida, Bahadurgarh, and Ballabhgarh in the National Capital Region of India. The system consists of 10 colour-coded lines serving 271 stations, with a total length of 374.466 km (232.682 mi). It is India's largest and busiest metro rail system. The metro has a mix of underground, at-grade, and elevated stations using broad-gauge and standard-gauge tracks. The metro makes over 4,300 trips daily.