The Supertech twin towers in Uttar Pradesh's Noida were demolished on Sunday afternoon. The two towers crumbled into an estimated 55-80,000 tonnes of debris within nine seconds.
The buildings were rigged thousands of kilograms of explosives. Around 5,000 residents of nearby buildings had vacated their houses and a no-flying-zone was also declared at the time of the demolition around the site.
Final checks along with the last round of putting precautionary measures in place for the demolition began on Saturday and were complete by Sunday morning, hours before the demolition.
Here we explain how Noida twin towers were demolished, the arrangements in place, and what's expected now as the vicinity of the demolished towers is wrapped in plumes of dust.
How Noida twin towers were demolished
The two buildings were 100 metres tall, taller than Delhi's iconic Qutub Minar. They crumbled into dust and debris within nine seconds.
The two towers were rigged with around 3,700 kg of explosives and were demolished with the "waterfall implosion" technique. This technique ensures that the building crumbles inwards and onto itself like a waterfall hits the Earth.
"Explosives are strategically placed and detonated to ensure minimal damage to the surroundings. The process behind the implosion includes the gradual weakening of critical supports of the building, i.e., removing the structures that will help resist the gravitational force," explains The Indian Express.
Edifice, the company that carried out the demolition, said the waterfall implosion technique is the one that takes the shortest possible time and causes minimal disturbance to nearby residents.
All the preparations were complete on Saturday itself. On Saturday, it's understood that the two towers were interconnected and a 100 metre-long cable was connected from the structures to the exploder, from where the button was pressed that blasted the two towers.
Officials said that no immediate adverse event was reported and demolition went smootly. However, they added that the picture would clearer once the dust settles and detailed assessments are made. Edifice officials would also hold a press conference in the evening.
Evacuation and precautionary arrangements in place
A range of precautions were taken to ensure that the explosions only brought the buildings downward and that no debris is flown sideways that damages nearby buildings. Nearby buildings were wrapped in protective sheets to shield against the dust and debris they would be exposed to. But residents were still concerned about their safety.
Plates were also placed above gas pipelines to protect them, though an official said that they are designed to withstand even mild earthquakes.
"GAIL pipelines have been designed as per the Richter Scale 4 here. It is 3 meters under the ground. Still, we have placed plates above it. 100 per cent there won't be any problem with the GAIL pipelines," said Jigar Chheda of Edifice to ANI.
Around 5,000 residents of Emerald Court and adjoining ATS Village societies vacated their premises by 7 am on Sunday. They also removed nearly 3,000 vehicles and 150-200 pets. Animal activists were also rescuing animals in the area so were not at risk at the time of the explosions.
An exclusion zone was created in a radius of up to 500 metres around Noida twin towers where no human or animal was be allowed except for the team of Indian and foreign blasters engaged in the demolition.
Diversions were placed on roads leading to the twin towers in Noida Sector 93A from Sunday morning while the Noida-Greater Noida Expressway, barely 200 metres from the demolition site, was closed for vehicular movement from 2 pm to 3 pm, according to officials.
Officials added that Google maps have updated feeds for diversions and real-time traffic situations. Arrangements have also been made for movement of emergency vehicles.
DCP (Central Noida) Rajesh S on Saturday said around 400 police personnel would be deployed for law and order duty, while Pradeshik Armed Constabulary (PAC) and National Disaster Response Force (NDRF) personnel would also be on the ground for any contingencies.
Noida Chief Medical Officer Dr Sunil Sharma said the health department would station six ambulances at the site equipped with officials and medicines. Beds have been reserved at the district hospital and private medical facilities Yatharth, Felix and Jaypee too.
The dust cloud and the debris
The demolition of Noida twin towers produced huge clouds of dust that enveloped the vicinity of towers. Additionally, the demolition is expected to have produced an estimated 55-80,000 tonnes of debris which would take months to be cleared.
Authorities have deployed water tankers, water-sprays from rooftops, and anti-smog guns to wash the dust in the air in order improve the visibility and remove pollutants from the air.
Dust cloud is expected to move towards Greater Noida and Bulandshahr in Uttar Pradesh as the wind is blowing eastward on Sunday. For the past one week, the wind was blowing westward which could have taken the dust cloud to Delhi.
According to the officials, a wind direction towards the west would have been more favourable as the dust cloud and particles would have flown towards an open park instead of the residential parks behind the twin towers.
"Cleaning is being done, gas and electricity supply will be restored in the area while people will be allowed to enter the neighbouring societies after 6.30 pm," said Noida Authority CEO Ritu Maheshwari to ANI on clearing operations post-demolition.
(With PTI inputs)
