Sub Terrain Structure in Sector 1?

Came across this article yesterday, it mentions how IITR did not pass two P&B HC Construction proposals. The thing that stuck with me is that a sub terrain project got approved in the jungle area behind open hand monument. Does anyone know what this project is about ? The words are not quite clear in this article. Sub terrain just means underground. What, why hasn't been described. Making a parking doesn't make sense, it could also be an underground facility for government or military infrastructure. There's a similar article published on The Tribune as well, but that's pretty much it. Looking forward to more information on the same, thanks in advance! https://www.hindustantimes.com/cities/chandigarh=news/chandigarh-two-capitol-complex-projects-get-thumbs-down-from-iit-roorkee-101738785829785.html