In a first, Metrowater has introduced robotic desilters to pick up silt and solids clogging sewers. On a trial basis for a year, they have introduced three such machines, for Rs54 lakh plus CSR-funding from Oil and Natural Gas Corporation in Adyar, Teynampet and Thiru vi ka Nagar zones. The machine has a camera, a 13m-deep arm which can move 180degrees for effective cleaning. A workers lowers and maneuvers the arm and camera with levers in a modified minivan, picks up silt with the grabber-bucket. Further, the silt is mechanically sent to another storage container for further disposal. It also has a hydrogen sulphide gas detector which beeps on the gas presence, unlike the other desilters. The other desilting machines lack cameras, longer and moving arms to pick up solids from the sewer. Further, it takes around 30 min to desilt one machine hole with robotic sewers, while it takes an hour to desilt using the normal machine. So, the robotic desilter can desilt 8-10 sewer holes, while a normal one can do around 4-6.