The evacuation of around 5,000 residents of the two housing societies near Supertech twin towers here is complete, officials said on Sunday as the stage is set to raze to the ground the nearly 100-metre-tall illegal structures.

The evacuation of residents of the Emerald Court and the ATS Village societies was scheduled to be completed by 7 am but took a little longer, police officials said.

Cooking gas and power supply lines have also been discontinued in the two societies in Sector 93A in view of the implosion planned at 2.30 pm on Sunday, an official overseeing the evacuation exercise told PTI.

"The evacuation has been completed. Cooking gas and electricity supplies have been discontinued. They will be resumed after security clearance post demolition later," the officer said. Besides the residents, their vehicles and pets have also been moved out, the official added.

However, private security guards and some representatives of residents' group will stay within the societies till around 1 pm, after which both premises would be totally vacant, the officer said.

D-day for the structures

Over 3,700 kg explosives will be used to bring down the structures in pursuance of a Supreme Court order that found their construction within the Emerald Court society premises in violation of norms.

The towers — both taller than Delhi's iconic Qutub Minar — will be brought down in less than 15 seconds by waterfall implosion technique. They will be the tallest structures yet in India to be demolished, officials said.

The buildings closest to the twin towers are Aster 2 and Aster 3 of the Emerald Court society which are just nine metres away. The demolition would be done in a manner so as not to cause any structural damage to other buildings, they said.

While the nearby Noida-Greater Noida Expressway will be closed from 2.15 pm to 2.45 pm, the city will remain a no fly zone for drones. The air space in one nautical mile radius above the blast zone will also remain briefly unavailable for flights during demolition time, according to the Noida Authority.

All work related to placement of explosives and connecting them is already complete. The only part remaining is interconnecting the twin towers and placing a 100-metre-long cable from the structures to the exploder, from where the button would be pressed, project officials said on Saturday.

"Once we get the clearance from the police department that the exclusion zone is 100 per cent clear, then at 2.30 pm on Sunday we will press the button," Edifice Engineering's project manager Mayur Mehta had said.

‘100% confident’

He said only six people, including three foreign experts, Indian blaster Chetan Dutta, a police officer and himself, will remain within the exclusion zone to push the button for the blast.

Asked how confident he was regarding safe demolition, Mehta told PTI: "100 per cent. I don't have any other word. We are 100 per cent confident." Mehta's Mumbai-based Edifice Engineering has been tasked with safely pulling down the structures. Edifice has roped in South African experts Jet Demolitions for the project. The whole exercise is being overseen by the local Noida Authority.

His brother and Edifice Partner Utkarsh Mehta has assured residents of adjoining societies that there will be no damage to their homes except for chances of "cosmetic cracks" on outer paint and plasters of some structures.

On the duration of the demolition process, he said first all explosives would blast in a series from the bottom floor to the top in eight to nine seconds, and then the buildings would take another four to five seconds to come down — with the whole event taking place under 15 seconds.

"The buildings are planned to come down in the south-west direction, away from the nearby buildings and towards the open area," Utkrash Mehta said.

‘Diamond cutter’

On how many options they had for demolition of the twin towers, he said there are basically three techniques to safely raze down any structure of such a scale — diamond cutter, use of robots and implosion. "The technique is chosen on the basis of three parameters - cost, time and safety," he said.

He said the 'diamond cutter' would have taken over two years of time to completely demolish the twin towers safely, and its cost would have been five times of the implosion method.

On using robotics, Mehta said this technique would have caused a lot of noise over a period of 1.5 years to two years and disturbed the residents of nearby Emerald Court and ATS Village. "Its cost would have been less than the diamond cutter technique but more than implosion," he said.

The Edifice boss said since the Supreme Court had also ordered that this project should be done in the shortest possible time and with no disturbance to neighbouring residents, the implosion technique became the choice.

Meanwhile, in an advisory issued for public Saturday evening, the Noida Authority asked people, especially children, elderly and patients, living in nearby areas to wear face masks in the aftermath of the demolition as a precautionary measure.

The authority especially asked residents of nearby Parsvnath Prestige, Parsvnath Srishti societies, village Gejha and others in Sectors 93, 93A, 93B, 92 to wear face masks after 2.30 pm.