Answer: Devprayag-Janasu Tunnel (Tunnel No. 8)
Notes: Devprayag-Janasu Tunnel (Tunnel No. 8) on the Rishikesh-Karnaprayag Rail Link Project in Uttarakhand is 14.57 km long (uplink), making it India's longest railway tunnel. The tunnel achieved structural breakthrough in April 2025. A parallel 13.09 km downlink is also constructed. It surpassed the Pir Panjal Tunnel, which is 11.2 km long. The project is targeted for operation by December 2026.
