 Tank irrigation is practised by constructing mud banks across small streams to make a small reservoir which collect excess water during the rainy season.Tank use is especially critical in parts of South India without perennial rainfall where water supply replenishment is dependent on a cycle of dry seasons alternating with monsoon seasons.Water is considered a purifying and regenerative element in India, and is an essential element of prayer and ritual.Water is also revered because of its scarcity in western India where dry and monsoon seasons alternate and failure of the monsoon season means famine and death while plentiful water replacing irrigations sources is a time of rejoicing.