Asia’s first underground Hydel Project is located in which of the following…

CONCEPT: An underground hydel (hydroelectric) project houses its powerhouse inside a rock cavern excavated underground, rather than at the surface — a design used where steep, unstable, or space-constrained Himalayan terrain makes a conventional surface powerhouse impractical, while also protecting machinery from weather and, in sensitive border regions, security risks.

APPLICATION: The Bhaba Power House (Sanjay Jalvidyut Pariyojana), built on the Bhaba river (a tributary of the Sutlej) in Kinnaur district, Himachal Pradesh, is widely cited in Indian exam and GK reference sources as Asia's first underground hydroelectric power project, its entire powerhouse built inside an underground rock cavern.

CROSS-CHECK: Among the states offered here, only Himachal Pradesh's Bhaba scheme carries this specific exam-source attribution: Jammu and Kashmir's Baglihar (Chenab), Arunachal Pradesh's Ranganadi (Brahmaputra system), and Uttar Pradesh's Rihand (Son system) are all notable hydel projects but are not the one credited with this record. (Note: this 'Asia's first' label is the standard Indian exam/GK convention tested by this PYQ; some underground hydel stations outside India may predate it, but Himachal Pradesh remains the answer consistently keyed across Indian exam sources for this question.)