Crippling fluorosis occurs at what level ?: (A) 0.5-0.8 mg/litre, (B) 1.5 mg/litre, (C) 3-6 mg/litre, (D) > 10 mg/litre
Answer is D. Ans. is 'd' i.e., 10 mg/liter Crippling fluorosis This occurs at fluoride level > 10 mg/litre (PPM). Patient is crippled and bed ridden.