Assam Public Health Engineering Department officials were the first to detect fluoride in excess of permissible limit and endemic of fluorosis in May 1999 in Karbi Anglong though the diseases were prevalent for the last twenty years. Prior to that it was believed to exist no problem of fluoride in the North Eastern States  though sixteen other states of the country were identified as having excess fluoride and fluorosis endemic. Intensified water quality testing and monitoring and health survey have detected more and more areas to be fluoride and fluorosis endemic which include some parts of Nagaon and Kamrup districts besides Karbi Anglong.