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Twelve million tons of fluoride deposits are found in India from the Earth crust out of 85 million tons of total deposition (Teotia and Teotia 1984). Therefore, the contamination of fluoride has broadly spread at an alarming rate in the Indian scenario. In the capital city of India, Delhi, the percentage of groundwater crossing the maximum permissible limit of fluoride present in drinking water is around 50% (Datta et al. 1996). According to the report of Jacks et al. (2005), the main reason behind the higher concentration of fluoride ion found in the groundwater of many parts of India was due to the evapotranspiration of groundwater with residual alkalinity. In the southern parts of India, major proportion of fluoride contamination in groundwater is due to fluoride enriched rocks for instance, groundwater of Andhra Pradesh, precisely Nalgonda district has high fluoride level, i.e. 320–3100 mg/kg due to presence of fluoride‐rich granitic rocks. The average fluoride level found in the granites of Hyderabad is 910–920 mg/kg (Ramamohana Rao et al. 1993).

According to the investigation the two sites of Uttar Pradesh and Madhya Pradesh have considerably higher concentrations of fluoride, i.e. 0.1–0.3 mg/L (Das et al. 1981; Satsangi et al. 1998; Singh et al. 2001). The main cause of the increasing fluoride contamination in this region was predicted as deposition of soil dust. According to the study of Jain et al. (2000), in Haryana, wet deposition of crustal material increases the fluoride load. Thirteen sites in Madhya Pradesh show about 0.05–0.22 mg/L concentration of fluoride as reported by Chandrawanshi and Patel (1999) and the area is considerably close to the industrial aluminum plant. A recently reported evaluation of dry deposition near Agra, reported by Satsangi et al. (2002) shows higher amounts of fluoride due to atmospheric deposition. Several authors have claimed that the atmospheric deposition is mainly from the crustal source. Concentrations of fluoride in different regions are presented in Table 2.1.