Researchers in Switzerland estimate that 9% of the Indian population, mainly in rural areas, could be affected by excess fluoride present in underground wells. A hazard map offers authorities the possibility of targeted testing in problem areas. Fluoride ends up underground due to natural weathering and enters groundwater. However, excess fluoride (above World Health Organization threshold level of 1.5 milligrams per litre) can cause growth disorders, damage to teeth and bone deformation. Scientists at the Swiss Federal Institute of Aquatic Science and Technology (Eawag) have developed a computer model based on 13,000 fluoride measurements carried out by the Indian Central Ground Water Board between 2013 and 2015. Geology, topography, temperature and precipitation values were also fed into the model. A hazard map created by the researchers shows that northwestern (Delhi, Gujarat, Haryana, Punjab, and Rajasthan) and southern (Andhra Pradesh, Karnataka, Tamil Nadu and Telangana) ...
