High Quality Content by WIKIPEDIA articles! Mahanagar Telephone Nigam Limited (MTNL) (NSE: MTNL, BSE: 500108, NYSE: MTE) is a state-owned telecommunications service provider in the metro cities of Mumbai and New Delhi in India. The company was a monopoly until 1992, when the telecom sector was opened to other service providers. Transparency makes us different- is the motto of the company. In recent years, MTNL has been lossing revenue and market share heavily due immense competition in Indian telecom sector.