Finally tunnelling below Maidan and Mominpur station can start as the Ministry of Defence which owns the plots allows objections.

Normally an amount has to be paid as a rent to the Defence but because this is underground, MOD could not get any rent. The tunnel construction had been blocked for many years.

https://timesofindia.indiatimes.com/city/kolkata/defence-nod-makes-journey-of-joka-metro-project-easier/articleshow/77249361.cms