context: The project started work but due to financial constraints, transfer of underground services, suspension of court, suspension of irregular supply of raw materials etc. due to the closure of the project, the project was unnecessarily delayed. Finally, the special initiative, efficiency, and diplomatic foresight of Railway Minister Abu Barkat Ataur Gani Khan Chowdhury accelerated the project's work, and Prime Minister Indira Gandhi Esplanade-Bhabanomir (Netaji Bhagwati) Neyarji Bhagya. Kolkata Metro inaugurated India's first and the fifth Asia Metro service on the route. [3] Launched on November 12 that year The Dumdum-Belgacchia route is 2.5 km long. It is to be noted that this is the longest station distance of the Kolkata Metro. [3] When the metro was extended from Talliganj on April 7, the task of completing the 1.5 km route from Esplanade to Talliganj was completed. [3]
question: When was the Kolkata Metro first built?