Fluorine, a highly reactive gas seldom occur in nature in elemental form. It has very high affinity to combine with other elements or molecules and form fluorides.
In nature, the most common fluoride containing compounds are 3 · calcium fluorite (Fluorspar; CaF2) · Cryolite (Sodium Aluminium Fluoride; Na3AIF6) and · Calcium phosphate (Apatite) complex.
The geological crust in India is very rich in fluoride bearing minerals. Though the country is mineral rich, it has its own problems too.
Fluoride is known to leach out and contaminate the underground aquifers.
In India a large population in villages depend upon ground water drawn through hand-pumps, tube wells (energized) and open wells, for consumption · consuming untreated groundwater led to excess fluoride entry to the body.
The urban population too, due to shortage of treated water, are dependent on ground water to a large extend.
Groundwater used maximally for irrigation for agricultural purposes, the crops are also contaminated with high fluoride.
India has a major public health problem as a result of ingestion of excess fluoride through drinking water and food (agricultural crops) besides processed food.