Answer: Hirakud Dam (near Sambalpur, Odisha)
- Constructed across the Mahanadi River; work began in 1948 and the dam was commissioned in the 1950s.
- Among the world’s longest earthen dams with long earthen dykes creating the vast Hirakud Reservoir.
- Multipurpose project: flood control in the Mahanadi delta, irrigation for lakhs of hectares, and hydropower generation.
- Supports industry and drinking-water supply in western Odisha.