The researchers at Bhabha Atomic Research Centre (BARC) in Mumbai, India, have developed a water purification technologies which is relatively simple and inexpensive to install, operate, and maintain. They have used carbon nanotubes, hollow carbon fibers. The unique chemical properties of carbon nanotubes mean that only very small molecules, such as water molecules can pass along their interiors, whereas viruses, bacteria, toxic metal ions, and large noxious organic molecules cannot. The smooth and water repellant interior of carbon nanotubes based filter based would be very efficient, allowing a high flow rate of water through the filter without fouling. This systems based on carbon nanotubes can remove arsenic, fluoride, heavy metals and toxic organic chemicals. It is claimed that the power needed to drive water through such a system will be low compared to conventional membrane technology.