VJNNS, NGO operating in Tribal villages of Visakhapatnam district has designed a Gravity fed water supply system (GFWSS) for vulnerable communit... Published on April 15, 2015 15:05 by Pallavi BharadwajVJNNS, NGO operating in Tribal villages of Visakhapatnam district has designed a Gravity fed water supply system (GFWSS) for vulnerable communities suffering due to non-availability of water. https://www.youtube.com/watch?v=KWL-YGd1pdo