Giving a major push to its Phase-III expansion, Delhi Metro has deployed as many as 19 Tunnel Boring Machines (TBM) which are working simultaneously below several critical junctions of the national Capital. Apart from engaging the TBMs, Delhi Metro Rail Corporation (DMRC) has also initiated a total of 33 tunnelling drives across the city in places around Hauz Khas, IIT, Lajpat Nagar, Kalkaji and also beneath Old Delhi areas. According to officials, the task has been challenging as such a massive tunnelling activity involves risks especially when the construction is undertaken below congested localities or below railway tracks, flyovers, existing metro viaducts or tunnels.