The Sela Tunnel project is estimated to cost Rs 687 crore and covers a total distance of 12.04 kilometres and consists of two tunnels of 1790 metres and 475 metres each.

https://www.eastmojo.com/arunachal-pradesh/2021/09/27/arunachal-governor-inspects-sela-tunnel-project-work-praises-bro/