India's deepest evacuation shaft will be built as part of the Kolkata-Howrah metro line, which is set to create history. Enhancing the safety and effectiveness of the metro system is the goal of this project. The planned East-West Metro segment connecting Kolkata and Howrah would have another engineering marvel in addition to being India's first under-river tunnel.

The ventilation-evacuation shaft, equivalent to a 15-story skyscraper, will be the deepest in the whole country. To be evacuated out of the shaft, which is located close to the Brabourne Road flyover, passengers would need to ascend the entire height (273 steps). The modified Esplanade-Howrah Maidan segment of East-West Metro is prepared for operation. In 2019, the 4.8-kilometer stretch's tunnels and three of the four stations were structurally finished.

The 520-meter twin tunnels at the Howrah Metro station fall 30 meters into the river. They then cross the riverbank and descend to a depth of 37 meters. An expert from Kolkata Metro Rail Corporation (KMRC), the organization in charge of carrying out the 16-kilometer East-West Metro, was heard stating that the structure was constructed using cutting-edge engineering methods to get over geological obstacles and minimize any effects on the Circular Railway line. 

In order to prioritize safety, elevators that run on electricity were not installed. Additionally, they examined passenger safety in emergency situations, including fire or smoke. Furthermore, Mr. Biswas added that evacuation shafts are required if there are more than 762 meters between two stations, according to National Fire Protection Association (NFPA) recommendations. Alternatively, every 244 meters, cross-passages could be constructed. Submerged beneath the river, that scenario was not possible. As a result, they managed to create the deepest ventilation shaft in India, exceeding the typical 16–20 m ones that have been built beforehand.

The Kolkata Howrah metro line continues to be innovating and evolving, and the authorities are dedicated to ensuring the passengers' safety and comfort.