District-wise Geospatial Distribution of Fluoride in Groundwater of Uttar Pradesh, India: A Narrative Review based on Secondary Data Synthesis

Globally, fluoride contamination in groundwater is a major environmental and public health concern. Current district-level fluoride mapping is inadequate in Uttar Pradesh, India, as data available from the early 2000s no longer accurately reflects present-day groundwater fluoride contamination. The present study synthesised secondary data to analyse the distribution of fluoride levels, particularly where concentrations exceed the permissible limit of 1.5 mg/L, and to understand environmental influences on fluoride distribution. A comprehensive search was conducted using MEDLINE (PubMed), Google Scholar, Embase, reports from governmental and institutional agencies, and public health databases related to fluoride contamination, its health implications, and district-level fluoride mapping studies published between 2000 and 2024. The findings of present review emphasise substantial variation in fluoride contamination across different districts of Uttar Pradesh, with some regions showing very high concentrations. Reported fluoride levels ranged from marginal exceedances to extreme hotspots exceeding 20–30 mg/L, highlighting the need for a multidisciplinary approach integrating environmental management, public health strategies, and sustainable water resource planning.