Crippling fluorosis occurs at what level ?
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.
0.5-0.8 mg/litre
1.5 mg/litre
3-6 mg/litre
> 10 mg/litre