Mahakaran (also known as New Mahakaran) (both names are officially correct), is a metro station on Green Line of Kolkata Metro, located in B.B.D. Bagh. There are many British heritage buildings near the station with the Lal Dighi adjoining it. The tracks leaving the station towards Howrah go underneath the Hooghly River through the biggest underwater metro tunnel of India. The station was completed and opened on 6 March 2024. The station, though comparing without platform screen doors, may look similar to any Blue Line underground station, but it is actually very different as it is designed with world class facilities and murals that pay tribute to the locality and Indian freedom fighters. The nearest railway station is B.B.D. Bagh railway station. Just before the tunnel enters the underwater segment, lies a ventilation shaft on the Kolkata bank of Hooghly River, which is the deepest of its kind in India, at 44 metres (144 ft) below ground level.