There are 67 navigable rivers in the state of Kerala. A peculiar feature of Kerala: canals link the lakes and backwaters to form an uninterrupted inland water navigation system. The T S (Travancore-Shornur) Canal, built in 1880, was the main water transport route from Trivandrum to Cochin and beyond till the 1950s. It was the main trade route, especially for transporting spices and grains to the ancient port of Kollam. The per km cost of development of a waterway is insignificant compared to a rail or highway. The maintenance cost of a waterway is also lower. The time taken to develop waterway routes is negligible. IWT is more environmentally friendly than either road or rail.