The CMC housing estate for NRIs, a block of which is in danger of collapsing as it stands on a crumbling sewer. Picture by Sanat Kumar Sinha

A block in the civic body’s NRI housing complex on DL Khan Road can cave in and there can be a crisis of drainage in and around Bhowanipore, feel civic engineers. The building is founded on a century-old underground sewer, which is on the verge of collapse.

Engineers belonging to the drainage department of the Calcutta Municipal Corporation (CMC), “discovered” during desilting operations that a portion of the apartment block lies directly above a five-ft-wide and seven-ft-deep underground brick conduit laid during the Raj, which is now crumbling.

“In case the bricks collapse, the housing estate will be in grave risk and the drainage services of a vast area in Bhowanipore will be in jeopardy,” said Tushar Ghosh, acting chief engineer (drainage and sewerage), CMC.

“We can’t even reach the sewer for repair work,” the engineer added.

“I don’t know how the civic engineers who sanctioned the housing estate could have overlooked this. This has assumed dangerous proportions,” said mayoral council member (drainage and sewerage) Farzana Choudhury.

“It is surprising that there was no one in the CMC in the past 12 years who knew that the sewer existed,” said mayor Bikash Ranjan Bhattacharyya.

“I have directed Gorachand Mondol, director -general (buildings), and Nilangshu Bose, chief engineer (projects and development), to submit a technical report on the safety of the housing estate after surveying the situation,” said municipal commissioner Alapan Bandyopadhyay.

The “discovery” of the underground brick sewer has led to the turning down of a proposal by Trinamul Congress councillor Anil Mukherjee to construct a community hall on DL Khan Road.

The drainage department is now planning to lay an alternative bypass sewer line to prevent toilet run-off in Bhowanipore.

In 1994,the CMC took up the project to construct 42 flats for NRIs in two blocks on its land on DL Khan Road.

The decade-old project was conceived, designed and constructed under the supervision of the then director-general (projects and development) of the CMC.