I'm not sure if someone has already posted this here, but Cal Newport had a nice presentation summarizing what we know about the effects of social media usage on children.
The net number (669 million) looks wrong. India's population is around 1.4 billion, so this would mean a data leak of nearly 1 in 2 Indians. If we further remove children below 14 (30% of India) who are unlikely to have data of their own and others who are completely off any of the data leak sources, the number given here would mean everyone in India has had their data leaked!
The data distribution given in the article seems to add to approximately 7 crores (70 million). I think there is a misplaced decimal somewhere. In all probability it is 6.69 crores (66.9 million). Still very significant, though.