The Delhi Metro is a rapid transit system serving Delhi, Gurgaon, Noida and Ghaziabad in the National Capital Region of India. The network consists of six lines with a total length of 189.63 kilometres (117.83 mi) with 142 stations of which 35 are underground. It has a combination of elevated, at-grade and underground lines and uses both broad gauge and standard gauge rolling stock. Four types of rolling stock are used: Mitsubishi-ROTEM Broad gauge, Bombardier MOVIA, Mitsubishi-ROTEM Standard gauge and CAF Beasain Standard gauge.

Delhi Metro is being built and operated by the Delhi Metro Rail Corporation Limited (DMRC). As of November 2010, DMRC operates around 2,700 trips daily between 6:00 and 23:00 running with an interval of 2 minutes 30 seconds between trains at peak frequency. The trains are mainly of four coaches, but due to increase in passengers numbers, six-coach trains are also added on the Red Line (Dilshad Garden to Rithala), Yellow Line (Jahangirpuri to HUDA city centre), Blue Line (Dwarka sec −21 to Vaishali/NOIDA city centre) and Violet Line (Central Secretariat to Badarpur). The power output is supplied by 25-kilovolt, 50 Hertz alternating current through overhead catenary. The metro has an average daily ridership of 1.8 million commuters, and, as of July 2011, had carried over 1.25 billion commuters since its inception. The Delhi Metro Rail Corporation has been certified by the United Nations as the first metro rail and rail-based system in the world to get “carbon credits for reducing greenhouse gas emissions” and helping in reducing pollution levels in the city by 630,000 tons (630 Gg) every year.

Mangu Singh is the second the current managing director of Delhi Metro. He took over as the managing director of Delhi Metro after E. Sreedharan, the former managing director of Delhi Metro, retired from service on 31 December 2011. He is an Indian Railways Service of Engineers (IRSE) officer of the 1981 batch.

Mangu Singh was born in Bijnor, a small town in Uttar Pradesh. He completed his Civil Engineering from Roorkee University (presently IIT Roorkee) in 1979..