Down To Earth magazine (www.downtoearth.org.in) covers the water purifier market in a relevant and important story in their current issue. It covers the different kinds of water purification technology and what they are effective against. It raises questions about Reverse Osmosis and its relevance in the face of widespread adoption. On the Water Portal, see : https://www.indiawaterportal.org/Network/askq/kb/?CategoryID=14 for extensive question/answers on water quality and: https://www.indiawaterportal.org/Network/askq/kb/?CategoryID=20 for a FAQ on TDS