The Chennai Metro is a rapid transit system serving the city of Chennai, Tamil Nadu, India. It is the third longest metro system in India after Delhi Metro and Hyderabad metro. The system commenced service in 2015 after partially opening the first phase of the project. The network consists of two colour-coded lines covering a length of 55 kilometres (34 mi). The Chennai Metro Rail Limited (CMRL), a joint venture between Government of India and the Government of Tamil Nadu built and operates the Chennai Metro.