Which district of the following does not have Fluoride contamination in ground water?

Correct answer: Nadia

Explanation: The correct answer is D. Nadia. Fluoride contamination is often linked to geogenic factors, especially in areas with igneous and metamorphic rock formations, where groundwater movement dissolves fluoride-bearing minerals. Nadia district is not significantly affected by fluoride contamination in groundwater, according to various environmental and hydrological studies in West Bengal. In contrast, districts like Purulia, Bankura, and Birbhum, which lie in the lateritic and hard rock regions of western West Bengal, are known to suffer from high levels of naturally occurring fluoride in their groundwater.