It could either be a matter of a few seconds or a tedious process of one-and-a-half to two years to safely demolish Supertech's illegal twin towers in Noida.

The nearly 100-metre-tall structures taller than the Qutub Minar will be safely pulled down on August 28 using a demolition method known as the 'waterfall implosion' technique, Edifice Engineering officials said.

The towers Apex (32 storeys) and Ceyane (29 storeys) will come down in less than 15 seconds literally like a house of cards, while ensuring that no damage is caused to nearby buildings the closest two being just nine metres away.

Edifice partner Utkarsh Mehta told PTI that they are "150 per cent" confident that the towers will come down safely and in the direction as envisaged by them, assuring residents of no damage to their homes except for chances of "cosmetic cracks" on outer paint and plasters of some structures.

On how many options they had for demolition of the twin towers, Mehta 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.

"There we would have to slowly cut down every column, wall and beam from top to bottom using cranes," Mehta said.

On using robotics, he 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 for the project.

"As Edifice and our South African expert partner Jet Demolitions also had precedence and experience from the demolition of Maradu complexes in Kochi, Kerala, we decided to go ahead accordingly," he added.

The twin towers are being demolished in pursuance of a Supreme Court order of August 2021 that found their construction within the Emerald Court society premises in violation of norms.

Over 5,000 residents of Emerald Court and ATS Village the two closest societies to the twin towers will be evacuated on Sunday by 7 am. Some 2,700 of their vehicles will also be removed from the premises and the residents will have to take away their pets too with them.

An exclusion zone will be created in a radius of up to 500 metres around the twin towers where no human or animal would be allowed except for a team of Indian and foreign blasters engaged in the demolition.

Over 3,700 kg explosives is being used to implode the Apex and the Ceyane towers, leaving behind an estimated 55,000 tonnes to 80,000 tonnes of debris which would take at least three months to be cleared from the site.