Following are some of the circumstances where NATM is preferred over TBM machines: 1. If the geology of ground is extremely varying, in such cases, the approach can be modified according to the modifications in the geology. 2. NATM is a versatile technology. It can be used to construct the various profiles of the tunnels. This can be achieved by altering the blasting patterns as per the need of the tunnel’s geometry. 3. TBM setup is often challenging due to the congestion and insufficient space at the site. In such cases, NATM is preferred as the tunneling method.