The suddenness of Karachi’s sewers
Dread suddenness in Karachi―in the shape of shocks that keep us in a permanent state of stress.
Consider these examples by degree: Heading to North Karachi, I will suddenly find myself frightened and lost in the thickets of an unfamiliar neighborhood because I unknowingly took the wrong exit off a sudden new flyover.
Passing through PECHS, I am momentarily disoriented because the brain registered what the corner of the eye barely caught: a sudden gaping space where something once stood, like the saddle in the gum where a tooth once sat. I realize that gaping hole is the plot of yet another Art Deco property that has been torn down to make way for middle-class apartments. Our vintage neighborhoods have come to resemble sinister gummy grins that form when tooth after tooth has been extracted or fallen out from decay or disease.

Suddenness in smarter cities is wielded as an instrument of marvel. I’ve turned a corner in Madrid, Seoul, London, Paris, Singapore, to come upon a sudden sight of breathtaking wonder, a giant bronze frog, a dancing fountain to delight children, a space cleverly sculpted for pedestrian pleasure. In Karachi you will turn a corner and encounter something that takes your breath away―a tree stump, a neoliberal prescription to feel fuzzy about Karachi, the ruins of a heritage building―but it feels more like that microsecond when your breathing is stoppered after a long hoarse scream.
I dwell on suddenness because I suspect it is what emerged from how this summer’s monsoon terror changed us under our skins.
A giant hole had appeared in front of CM House. The road had just suddenly caved in. From the distance the neat black cut-out circle looked like an optical illusion or an anti-mirage, a flattened 2D image in a 3D-scape
In July, I was driving to work via Dr Ziauddin Ahmed Road that takes me to the Sheraton-PIDC signal. I started to feel dismay as the traffic was stuck mid-way in what is usually a fast-flowing artery. They were diverting us left onto Brunton Road at the State Life building. As my car crawled forward, I craned my neck right to see why the road had been closed: A giant hole had appeared in front of CM House. The road had just suddenly caved in. From the distance the neat black cut-out circle looked like an optical illusion or an anti-mirage, a flattened 2D image in a 3D-scape.

That image stayed with me as we battled the monsoon’s unexpected mood through August. What if I had been in that spot at the signal when the road collapsed? How can we tolerate a chunk of the road suddenly sinking? How can we ever drive again knowing we could be sucked into the bowels of the earth in a hot second? Terror is the paralysis of knowing that as we lurch from moment to moment in this life, we do so absolutely blind to what could happen next. Anything could suddenly happen in Karachi, just like that cloudburst at the beginning of August that left so many people helpless and stranded across the city.
I reckon, however, that the antidote to these anxieties is knowingness. And so, when the water drained, and I began the forgetting of the monsoon’s trauma, my fear gave way to anger. I would not countenance roads caving in. Why did this happen? How widespread was it? Was anything being done? My journalistic anger led me to the door of Ayoob Shaikh, who was until recently running Karachi’s water and sewerage board, and is known as one of the most knowledgeable of engineers the institution has ever had.

Ayoob Shaikh confirmed that indeed, it was a phenomenon and they had fixed 200 such craters since the rains (see list below).
“The major problem which we are facing, mainly in district South or the Old City area where the system is really old, is the corrosion of the concrete of the pipe,” he explained.
These sewage pipelines carry whatever is flushed from your toilet. This is sewerage that has biomass or sludge. When KW&SB engineers design our pipes, they see to it that the maximum flow of sewerage will be 80% of the diameter so the top of the pipe always stays empty. They don’t want the pipe to be full.

“The pipelines are designed for self-cleansing velocities,” he said. “So the sludge should normally not settle but keep moving through the pipe. It should head to the pumping station and eventually to the treatment site. But because our pumping stations aren’t working properly or malfunction, there is less flow in the pipes.”
The biomass thus starts settling in them. It then starts decaying, decomposing and degenerating, and gases are let off. The gases come in contact with the top of the pipeline, called the crown, which is a moist place. So the sulfur gas meets the moisture and turns into sulphuric acid, the Nitrous oxide gas from the sludge produces nitric acid. “These acids cling to the internal surface of the pipeline and really weaken it,” he added.
Additionally, when it rains, the (water’s) surcharge load on the road surface, or the earth cover on top of the pipeline, becomes saturated and heavy. This weight bears down on the already weak crown of the pipeline. That is when it caves in. “Once you see a collapse, we see it is good for the whole stretch of the sewer and it means it has outlived its lifetime,” Shaikh said. These pipes were supposed to last 35 years but they are collapsing before their time.
In Karachi’s Old City areas they used to have a way of dealing with the acid buildup, by the way. There were shafts for gas release. But as highrises developed people started removing the vent shafts because they said they smelled. Little did they know that they were destroying a defense system that kept their sewers in good shape.
In Karachi’s Old City areas they used to have a way of dealing with the acid buildup: vent shafts
Aftab Chandio, the chief engineer of sewerage, oversaw the work to replace the collapsed part outside CM House with 300 feet of a new 72-inch pipeline. “It was almost 25 feet deep,” he explained. “We worked 24 hours for four days.” It’s a 1960s system, he said, what do you expect?
I expect that the people in charge of this city will do what they can to prevent and preempt giant holes from opening up in the ground beneath our feet. Are we not already becoming progressively psychically scarred from the city-wide infrastructure destruction wrought by each monsoon deluge? I quote from Camille Paglia: “Civilized man conceals from himself the extent of his subordination to nature. The grandeur of culture, the consolation of religion absorb his attention and win his faith. But let nature shrug, and all is in ruin. Fire, flood, lightning… Civilized life requires a state of illusion.”
We have mostly been able to suspend our hearts and minds to continue to bear living in Karachi. We grew used to the terror of the target killing, a summer of sky-high homicide rates. That was supplanted by the terror of life-snatching Covid, as we dystopically stood at distances in front of biers at funerals we feared would herald our own. This year, the climate crisis visited upon us a terror of national proportions. I used to dread the suddenness of the demise of bad romances, the emotional autopsies and bitter unfinished goodbyes. How pitiful those tiny terrors of abandonment were. Today I fear the suddenness of sinking sewers.
This is the list of 148 sewer collapses that KW&SB fixed:
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