Kathmandu, September 14 Police have arrested 19 persons for allegedly extracting sand from the Manahara Khola in an unauthorised way. A team of Metropolitan Police Circle, Baneshwor, had caught them in the act of loading sand onto the trucks in Pepsicola and Kageshwori Manahara this morning. They have been handed over to the Office of District Coordination Committee, Kathmandu for legal action. Seven trucks used for ferrying the illegally extracted sand have also been impounded. DDC is the authority that designates the locations and grants permission for extraction of sand and pebbles. Tax is levied on stones, sand and slates so extracted as per the Local Self Governance Regulation, 1999. Anyone extracting sand and stones from rivers is required  to pay tax to the DDC at the rate determined by the district council. Sand-mining from the already depleted rivers of Kathmandu Valley has become a money-spinner for businessmen here. However, the government has not been able to control illegal sand-mining activities, which environmental activists fear could result in disastrous consequences for the Valley. Every year, the monsoon brings sands to the Hanumante and Manahara rivers. As soon as the rainy season retreats, sand-mining resumes on a war footing when contractors compete to extract sand.