Tokyo (AFP) - Japan's Panasonic will develop a water purification system together with India's Tata Group, tapping into a fast-growing market in Asia, a media report said Saturday.The electronics giant has developed a prototype of a device that will detoxify harmful substances in groundwater, making it potentially safe to drink, the Japanese economic daily Nikkei said.The system, which is compact enough be carried in a small truck, has been designed to serve small rural communities in India where water-supply infrastructure is underdeveloped, the report said.