Annual Maintenance Contract of 2 X 40 TR Voltas Make Chiller Unit and Supply of Necessary Spare Part for two years at Rihand Hydro Power Station, Pipri, Distt. Sonebhadra Annual Maintenance Contract of 2 X 40 TR Voltas Make Chiller Unit and Supply of Necessary Spare Part for two years at Rihand Hydro Power Station, Pipri, Distt. Sonebhadra