What happened to buildings along Mumbai's Marine Drive after tetrapods that protect from tides were removed?

Recently, residents of a few buildings on Mumbai’s Marine Drive complained of “unusual vibration” during high-tide hours over the past weekend. The incident was reported to the Brihanmumbai Municipal Corporation (BMC) which sent a team to visit the site on Monday. According to Mumbai Mirror, the Nariman Point Churchgate Citizens Welfare Trust or NPCCA on Saturday raised the matter in a letter to the BMC, stating that several residents of Shree Niketan and Gobind Mahal societies have been noticing vibrations in the structures that “feel like tremors”. Since the BMC’s visit to the site on the iconic 3-km promenade in south Mumbai, the body has started re-installing tetrapods to “allay the fears of citizens of the said societies.” What are tetrapods? Tetrapods are four-legged concrete structures that are placed along coastlines to prevent erosion and water damage. According to The Indian Express, these structures were first used in France in the late 1940s to protect the shore from the sea. When placed together in an interlocking but porous barrier, tetrapods can act as a buffer between the land and water while dissipating the power of waves and currents. Each tetrapod can weigh about two tonnes, sometimes up to 10 tonnes. Tetrapods were first placed along Marine Drive in the late 1990s to maintain the reclaimed shoreline in South Mumbai. Why were the tetrapods removed? The tetrapods were removed for the ongoing Coastal Road Project, under which 10.58 km of coastal road will be made from Princess Street in Marine Drive to the Worli end of the Bandra-Worli sea link. According to The Indian Express, there are over 6,000 tetrapods along Marine drive alone. How bad were the vibrations? The residents complained that there was “no doubt” that almost all the people living in the two buildings felt the tremors. “I would like to bring to your urgent notice that for the last few days, many residents of Shreeniketan and Gobind Mahal buildings (sea-facing buildings between G&F Road on Marine Drive) have been feeling vibrations. The vibrations come for 1 second and in intervals for a period of ~30-60 minutes in the afternoons. These vibrations feel like tremors akin to an earthquake. Many of us searched if there was an earthquake in Mumbai. Now imagine earthquake-like tremors 20-30 times in an hour,” the residents said in the letter to the BMC. Even though the BMC did not officially say that the removal of the tetrapods caused the vibrations, it did agree to re-install the structures. “To allay the fears of citizens of the said societies, BMC has asked the contractor to put the tetrapods back in place. The contractor has started the work of placing tetra pods at the said location,” the civic body has said. With inputs from agencies Read all the Latest News , Trending News ,  Cricket News , Bollywood News , India News and Entertainment News here. Follow us on Facebook, Twitter and Instagram.