This will be a Parallel Group, Double-Blind, Randomized Controlled Trial, over a period of 18 months. The study will be conducted in a randomly selected school of Karachi city. Participants will be the cohort of regular school children aged 12-14 years. Sample size for the present study attained was 330 (165 in both groups), expected attrition rate will be kept as 15%, so the total sample size is 330 + 50 = 380 (190 in each group).