Sisters Aritri and Pallabi Bhattacharya spent Friday evening on the footpath.

"Where will we sleep at night?" 16-year-old Aritri, a Class X student, asked sibling Pallabi as the duo squatted on the road outside their home.

When the MCom student said she did not know, Aritri remarked, more in hope than confidence: "The elders will work something out."

The students are among the 50-plus families grappling with homelessness after the collapse of the Vivekananda Road flyover.

Around noon on Friday, officials of the Calcutta Municipal Corporation (CMC) hung multiple metal signboards on five buildings near the spot where the flyover had crashed on Thursday, declaring them "dangerous".

An hour and a half later, cops from Posta police station came calling.

"The policemen asked us why we were risking our lives by staying in a building that had been declared dangerous by the civic body. Another team, comprising policemen and firemen, arrived soon after and said we could continue staying in our homes at our own risk. ' Thakte chaile apnader risk, corporation toh notice lagiye gechhe. Ebar apnara bujhhe nin (If you choose to stay, then you may do so at your own risk. The corporation has put up the notice. Now it is your call)," recounted Kaushik, another member of the Bhattacharya family.

The 15 members of the household stay on the ground floor of the three-storey building at 1 Kali Krishna Tagore Street, at the intersection where the under-construction flyover crashed. One of the beams of the structure scraped the balcony of the adjoining building - which the CMC has also declared "dangerous" - before landing outside the main gate to their home, almost blocking it with a heap of rubble.

The impact of the fall opened up several cracks in the building, which is over 100 years old and has been home to the family for just as long.

The sight of the cracks, as much as the official warnings, prompted the family members to vacate the building, although they were unsure whether that would mean spending the night in the open.

"This is our ancestral house. We have never ever considered staying elsewhere. This is hard for us," said Aritri and Pallabi's aunt Putul Bhattacharya.

The family's ancestral temple (Jorasanko Kali Mandir) is also on the ground floor of the building. The temple barely escaped being smashed by a falling metal beam of the flyover.

"We hold a puja at the temple every evening. This tradition will be broken for the first time," said Kaushik's uncle Kartik Bhattacharya.

Kaushik, who works in an IT firm in New Town, said the family had gathered all their valuables, testimonials and other portable items by 4pm and shifted these to their relatives and friends' homes.

"We don't know how long we can stay elsewhere," said Kaushik, who until last week used to wait outside his home to be picked up by his office car around the time the 40-metre span of the flyover came crashing down on Thursday.

"My office timings were advanced this week, so the car picked me up at 11.30am instead of 12.30pm. Otherwise, there would have been one more name in the list of the dead," said Kaushik.

The Malls of 265C Rabindra Sarani are in the same dilemma as the Bhattacharyas. This joint family of more than 12 members occupies the first floor. "Initially, the CMC officials told us that we could stay, provided we avoided using the front part of our building, which faces the Bhattacharyas' home. Then local MP Sudip Bandopadhyay visited our house at 7.45pm and advised us to move out by morning since the building had been declared unsafe by the CMC," said Bindu Mall, who runs a business.

Two members of the family are immobile. Goura Devi Mall, 84, and Mahati Mall, 88, have been bedridden for several months. Mahati has breathing problems and needs oxygen support for the greater part of the day.

"Till Thursday, we had a roof over our heads. Now we have been asked to move out and we don't know where to go. The staircase is narrow and we don't know how we will be able to take my elderly in-laws (Goura Devi and Mahati) downstairs," said Sashi Mall, 31, a homemaker.

Their building is over 125 years old and had shaken "violently" when the flyover collapsed at the crossing. Several cracks have opened up on the structure since.

While the Malls are still contemplating whether to move out or not, Gita Bhimani, 75, who stays in the same building, has left with her daughter Sujata Bhatter, 32, for Shibpur.

Sujata, dressed in a printed sari, carried in her left hand a suitcase into which she had stuffed her mother's belongings. With her right hand, she held her mother, who is yet to get over the shock of the collapse.

Gita stays alone in the building, in a wing different from the Malls.

"I have come to take my mother to Shibpur. She called me and told me that some policemen had asked her to vacate the building since it isn't safe. I rushed here from Shibpur in a taxi," Sujata said.

Officials of the CMC's building department said notices had been put up on five buildings near the site of the flyover collapse, asking the owners and occupants "either to repair or vacate" their homes for safety reasons. The police and the fire brigade have been informed about the notices.

Debasish Chakraborty, director-general (buildings II) in the CMC, said the notices had been issued under Section 411/1 of the CMC Act 1980, which does not make it mandatory for residents to vacate a building provided they repair it.

The notices do not mention a deadline within which the residents have to repair the building.

Mayor Sovan Chatterjee, who visited the area in the evening, said the civic body had asked the families to "temporarily" vacate the buildings. "If any family faces problems in shifting, we can arrange food and lodging," the mayor said.

But the families that Metro spoke to said civic officials who had come to paste notices declaring their houses unsafe did not offer them any assistance in finding alternative accommodation.

Sources in the CMC said the move to evacuate some buildings was meant to ensure that the civic body isn't blamed in the event of any portion of houses collapsing as a result of damage caused by the flyover crash.

The sources said that the residents of these buildings would not be evicted.

The state government has separately urged families living near the flyover crash site to shift elsewhere until the portions that had fallen were removed.

A team of experts, including senior engineers from multiple agencies, visited the area on Friday and advised senior government officials to move the residents to safety, the sources said.

Asked what the government would do if the families refused to shift, Atri Bhattacharya, information and cultural affairs secretary, said on Friday evening: "We will explain why we want them to shift."

Till late on Friday, the government hadn't announced any assistance to the families in repairing the buildings damaged by fragments of the flyover.

The families living in the five buildings notified as unsafe have been asked to stay away till such time the twisted pillars and beams that came off the flyover are removed, an officer at Posta police station said.