Social & Preventive Medicine Sequence of the substances used in the Nalgonda’s technique for defluoridation of water: March 2011 A Lime and then soda B Alum and then soda C Lime and then alum D Alum and then lime 💡 Explanation Sequence of the substances used in the Nalgonda's technique for defluoridation of water: March 2011 ✓ Correct Answer: C. Lime and then alum