On February 7 the Supreme Court had ordered the demolition of 100 metre tall, 40 storied, Supertech Limited’s illegal twin towers, which were constructed in violation of building bylaws.
After the date being changed several times, the Supreme court on August 12 said that the demolition will finally happen on August 28, 2:30 PM. In case the weather conditions are not conducive or there are any technical delays, the SC has given until September 4 for the demolition.
The demolition will now be done with a controlled explosion. However, there are major concerns regarding the environmental impact even a controlled explosion would have specially on the nearby buildings.
The biggest concern for the Uttar Pradesh Pollution Control Board (UPPCB), is the dust cloud that is likely to rise up post the demolition, and experts are worried about how this may affect the air quality in the surrounding locality.
“Because a large amount of concrete will be blasted, there certainly will be a high concentration for PM10 for a few days. PM 2.5 levels will be impacted, but more PM 10 will be released. Because it is concrete, coarser particles are going to be emitted more.”Dr Sachchida Nand Tripathi, Senior Professor of Civil Engineering, IIT Kanpur
SOPs Must to Minimise Environmental Impact
More than 3,500 kg of explosives will be used to bring down the 40-storey towers located in Noida Sector 93A.
These towers are taller than Delhi's Qutub Minar and will become India's highest structures ever to be demolished.
Edifice Engineering announced that they intend to create a controlled explosion and the area surrounding the site will be closed off with 225 tonnes of wired mesh made of galvanised iron and geo-textile approximately 110-km in length.
The surrounding community--Emerald Court and ATS Village, both societies will be covered in similar geo-textile cloth. Evacuation plans have been made for the people in these societies and those even further than the immediate blast impact range.
Residents in neighbouring societies have been asked to evacuate by 7 am the same day.
"This demolition is happening at such a scale for the first time and for sure our practices will fall short. Because these practices are for planned gradual work. They are not meant to take care of such a catastrophe that we are now looking at."Rajneesh Sareen, Programme Director, Sustainable Buildings and Habitat Programme, Centre for Science and Environment, New Delhi
While Edifice Engineering seems to be sticking as closely as possible to the guidelines provided for dust mitigation and control, we will only be able to see the impact of this event and the adverse effects that will follow post the demolition, say experts.
Dust Clouds, Smoke, and Noise Pollution Major Cause for Concern
The demolition will be responsible for massive dust clouds and smoke. This puts the people in the surrounding areas at a major health risk because the dust particles could cause irritation in the eyes, or nose as well as the smoke and dust being particularly hazardous to those with lung diseases or asthma.
"It is a very large scale demolition. But I don’t think there will be any lasting impacts. I doubt it. Maybe at the most for a week or so, the levels of dust would be elevated," said Dr Sachchida Nand Tripathi, a Senior Professor of Civil Engineering at IIT Kanpur who has done extensive work on air pollution.
"Since it is the demolition of largely concrete, it is mostly dust that will come out. It will settle down fast and using water sprinklers etc would help.”
The expectation holds that the dust cloud will dissipate soon, however, to be on the cautious side, Edifice Engineering has been taking measures.
Utkarsh Mehta from Edifice Engineering has said they had attempted using mist guns to minimize the damage cause by the dust cloud. However, these mist guns were only 10% effective.
There are a number of variables that would effect the time it would take for the dust cloud to disappear, this is especially dependent on the wind speed and weather on D-Day.
Due to the dust cloud, those who have evacuated the area will only be allowed to enter once the dust cloud has dissipated entirely and those with breathing problems have been advised to enter the area after a few days.
The best way to mitigate dust caused by construction or demolition is to create a green belt of trees around the explosion site, according to the Guidelines on Environmental Management of Construction and Demolition Waste, provided by the Central Pollution Control Board.
The air quality in the area will be continuously monitored for a few days prior to the explosion and the company has been asked to submit reports regarding the air quality and dust to the UPPCB for a week post explosion. The UPPCB reported that they will increase the frequency of air monitoring following the demolition.
'We Are Underprepared To Deal With Such An Event'
“The guidelines which we have are designed to control construction, which is a gradual process," said Rajneesh Sareen, Programme Director, Sustainable Buildings and Habitat Programme, Centre for Science and Environment.
He explained that this is deconstruction, and is not even happening at a slow pace. “It is happening in a few seconds. The fugitive dust emissions are going to be huge in this,” he added.
Commenting on the existing guidelines he said that these safeguards are to protect humans more and not particularly the environment. Measures like covering the building with sheets etc are an example of thing that are being done because they do understand that the dust bowl will be huge.
“You're bombarding a place and the requirements to curb environmental impact are not in place. So definitely the receptors are going to receive much more as compared to the safeguards that we have. We haven’t written codes and practices for these kinds of requirements.”Rajneesh Sareen, Programme Director, Sustainable Buildings and Habitat Programme, Centre for Science and Environment
Giving an example of a dump truck which unloads merely 5 tons of material, he said that even in that case the dumping generates fugitive dust and dust plumes despite following all ideal practices. So one can only imagine what will it mean for a huge concrete explosion like this.
“Fugitive dust means its a runaway. It will definitely rise. Whatever you might do.”
21,000 Cubic Meters of Debris Left Behind
Reports say that over 21,000 cubic meters of debris has been expected to come out of the explosion. It has been reported that the debris will be removed from the site over a period of three months.
The UNEP released a hierarchy for waste management in regards to construction and demolition that includes both the components of prevention and disposal of waste.
"There will be 5-6 storeys high debris. This is not what we have handled before. Whenever you move material from one location to another merely loading and unloading is bound to give you an interface in the environment,"Rajneesh Sareen, Programme Director, Sustainable Buildings and Habitat Programme, Centre for Science and Environment, New Delhi
"Things like moisture helps arrest this. Generally we look at 10-70% of the effectiveness of these techniques, even if they are done correctly and religiously, we get 70% effectiveness. This is the variation we consider in modelling. Here we don’t have any previous practices available," said Sareen.
The first priority being the reduction of waste production. Exploring options for recycling and reusing and finally disposing of any leftover waste.
"Local Authorities shall make provision for giving incentives for use of material made out of construction and demolition waste in the construction activity including in non-structural concrete, paving blocks, lower layers of road pavements, colony and rural roads."Environmental Management of C&D Waste, Central Pollution Control Board
There is also cause for concern over stray animals in the vicinity. However, people were assured by the Noida authorities that all stray animals will be evacuated from the vicinity of the blast two days prior. They will ensure that there are no strays on the day of the event and that all animals will be relocated to a shelter in Sector 94 according to Noida Authority.
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