The correct answer is option 1. Explanation & Key Takeaways: • Tehri Dam is not the highest dam in the World. • The world's tallest dam is the Jinping-I Dam in Sichuan, China. Sitting over the Yalong river, the dam uses a thin arch with double curvature. • The construction of the dam began on 12 November 2005, and the lengthy process of filling the dam with water, known as the impoundment, began on 8 October 2008, when a reservoir area of 82,55 km^(2) (888,557,250 ft^(2)) was finished. • The dam was built by CHIDI and is owned by the company Ertan Hydropower Production. • This renders the Yalong River, after the Yangtze River and the Jinsha River, China's third-largest hydropower centre. Important Notes: • The Bhakra Nangal Dam is a gravity dam on the Himachal Pradesh River Sutlej. With a height of 225 meters and the second largest dam in Asia, Bhakra Nangal is India's largest dam. • One of the world's longest dams is Hirakud. In the Sambalpur district of Odisha, Hirakud is the longest earthen dam in the world and stands over the mighty river, Mahanadi.