Delhi Metro

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.

Construction began in 1998, and the first elevated section (Shahdara to Tis Hazari) on the Red Line opened on 25 December 2002. The first underground section (Vishwavidyalaya to Kashmere Gate on the Yellow Line) opened on 20 December 2004. The network was developed in phases. Phase I was completed by 2006, followed by Phase II in 2011. Phase III was mostly complete by 2021, except for a small extension of the Airport Line, which opened in 2023. Work on Phase IV began on 30 December 2019.

The Delhi Metro Rail Corporation (DMRC), a joint venture between the Government of India and the Government of Delhi, built and operates the Delhi Metro. The DMRC was certified by the United Nations in 2011 as the first metro rail and rail-based system in the world to receive carbon credits for reducing greenhouse-gas emissions, reducing annual carbon emission levels in the city by 630,000 tonnes.

The Delhi Metro has interchanges with the Rapid Metro Gurgaon (via a shared ticketing system) and the Noida Metro. On 22 October 2019, the DMRC took over operations of the financially troubled Rapid Metro Gurgaon. The Delhi Metro's annual ridership was 235.8 crore (2.35 billion) in 2025. The system also has interchanges with the Delhi-Meerut RRTS, India's fastest urban regional transit system.