Very few people living in Guwahati must have heard of a river called Kalmoni, which is a part of the natural drainage system of the premier city. Kalmoni originates in the Garbhanga reserve forest in the south-western region of Guwahati as Satorgaon river. Once upon a time, local people in the Rani area also used to call it Godavari. Soon after originating inside the hills of Garbhanga it is joined by another stream (also called Satorgaon) from the right side, and after about eight kilometres it meets another hilly stream called Umkhaw. From that point it is known as Kalmoni. After flowing through Rani Tea Estate, it meets two more streams, one called Nalbari and the other Bamunguri. At a place called Sajanpara, it splits into two; the one flowing westwards joins Jagaliya river, while the other flows along the road connecting Rani with Azara. Seven kilometres after Azara, the Kalmoni takes a westward bend at Konpara, and travelling seven more kilometres, it empties into the Brahmaputra. It also has connections with Deepor Beel through a few culverts. Over the years, Kalmoni has become a double victim of pollution by the industrial units of Rani on the one hand and encroachment on the other hand. The people living beside the Kalmoni must also be held guilty of dumping garbage in it. While Kalmoni is one of the most neglected rivers of Guwahati, the Kalmoni basin bears lot of ecological significance for a large portion of western Guwahati, covering Deepor Beel, Rani, Borjhar (including the IAF base and LGBI Airport), Azara, and portions of eastern Palasbari as well. What most people, including those in the government, probably do not know is that Kalmoni is officially under the jurisdiction of the Kalmoni irrigation scheme of the Government of Assam. But the authorities concerned have chosen to keep eyes shut for reasons best known only to them. It is a matter worth appreciating that the government has recently launched a drive to free Kalmoni from encroachment. Kalmoni, like the Bharalu, Bahini and several other natural rivers, streams and brooks flowing through Guwahati, must be protected, along with the various water bodies and wetlands. Only then will Guwahati remain healthy and liveable. Every single encroacher, irrespective of whether he or she is a Bangladeshi or an indigenous Assamese, must be evicted without mercy.