Khoai in Bengali refers to a geological formation specifically in Birbhum, Bardhaman, and Bankura districts of West Bengal, India and some parts of Jharkhand, India that is made up of laterite soil rich in iron oxide, often in the shapes of tiny hills. This canyon like terrain is caused by wind and water erosion on red laterite soil.[1] Khoai is called part of the India's natural heritage.[2][3]