Minister of Public Works and Public Housing (PUPR) of Indonesia, Basuki Hadimuljono say long tunnels were made necessary in Semarang-Solo, to protect the environment and to keep the landscape beautiful.

https://www.cnbcindonesia.com/news/20200628133957-4-168575/top-jokowi-tol-sumatera-aceh-sigli-beroperasi-akhir-juni