Kolkata is one of the most populated cities in the world. So, after the success of underground transport system, popularly known as the Kolkata Metro Railways, a second line was planned. Originally planned in 1971, Kolkata metro line 1 started its operation in 1984. It is also called the Kolkata North South Metro. The line 2, or Kolkata East West Metro, has opened its doors to the general public on 14th February 2020.