This is great article, and another fine example of explaining a topic most have not encountered in language that’s easy to understand. You described the problem (not enough access to clean water in India), pointed out differences in geographical location and rainfall totals, government subsidies as incentives, and even countered with the issues of cost and complexity. I appreciated the explanation about grey water versus blackwater, and why one can be processed for reuse while the other cannot. From what I understand, India also has a big problem with black water treatment / containment / disposal, but I would imagine that, as priorities go, access to clean water is probably the higher priority.
Your article also points out (to us, the somewhat ignorant audience) that problems in developing nations are not restricted to a lack of food. Speaking for myself, I often attribute the plight of masses of poor people in developing countries strictly in terms of malnutrition and disease related to lack of food and medicine. This article is not only eye-opening, but provides enough information to easily understand that access to clean water in India is a major roadblock to continued development, education, and general well-being of Indians. Well done!