As part of the smart city project, less lime to travel for working class will increase the productivity of the city. Densely populated cities currently have no land for extremely fast transportaion. Such issues are also prevalent in Cities outside India. In order to solve this issue Elon Musk founder of Tesla, SpaceX has launched a New Company called 'The Boring Company' with an idea to create a network of tunnels below the surface of the earth. The goal is to reduce the cost of tunnel boring by a factor of more than 10. Current cost is 1 bllion dollar, the company is going to reduce it to 100 million dollars. Also the transportation will be cheaper than a bus with zero emission.
For details https://www.boringcompany.com/faq/