The IS:10500 (BIS, 2012) standard for drinking water in India specifies the permissible limit of fluoride in the absence of an alternative source as:

• A 1.5 mg/L ✓
• B 0.5 mg/L
• C 1.0 mg/L
• D 2.0 mg/L

Explanation

IS:10500 (BIS 2012) specifies an acceptable limit of 1.0 mg/L and a permissible limit in the absence of an alternative source of 1.5 mg/L for fluoride in drinking water. WHO's guideline value is also 1.5 mg/L. Fluoride below 0.5 mg/L causes dental caries; between 1.5–4 mg/L causes dental fluorosis; above 4 mg/L causes skeletal fluorosis. India has a dual burden — fluoride-deficient areas (Rajasthan, Himachal Pradesh) and fluoride-excess areas (Andhra Pradesh, Rajasthan, Uttar Pradesh).

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.