Synopsis This latest directory contains information of over 1300 tunnels and is the only publication which contains information about tunnelling and subsurface works in the country for various sectors. The details provided in this latest version include details of tunnels being used for different purposes like tunnels for hydroelectric and irrigation projects, metro tunnels, rail tunnels, water supply and sewerage tunnels, road tunnels etc. and details of other underground space works like power houses, desilting chambers, metro stations etc. The details also include the geological formations which have been encountered during the execution of the works.