Is Karachi ready to fight the next big heatwave?
Summer has only just begun but most parts of Karachi have already started to bake.
The Pakistan Meteorological Department (PMD) has warned citizens to brace themselves for temperatures that are likely to be more than one degree Celsius above average.
This, however, will hardly be the first heatwave to hit the city.
In 2015, 'an unending queue of corpses'
Three years ago, Karachi experienced the deadliest heatwave Pakistan had seen in over 50 years.
Starting June 19 that year, the coastal city witnessed sweltering heat that continued for more than five days and in its wake left over 1,200 people dead and 40,000 suffering from heatstroke and heat exhaustion.
"Most of those who died were the elderly suffering from other diseases that got exacerbated. They were from congested settlements and were among those living on the society's margins," says Dr Seemin Jamali, head of the emergency department at the Jinnah Postgraduate Medical Centre (JPMC), as she describes the mayhem that prevailed on the first day.
"If the army had not turned up, we would not have been able to control the situation," she adds.
Read more: Heatwave death toll in Sindh tops 1,000
For the next four to five days, the temperature hovered between 42-45C and would not let up.
Staff nurse Naseem Akhtar, who has been at JPMC's emergency department for over 29 years, remembers the "unending queue of corpses" coming into the hospital.
"It was the first time that I'd heard the term heatwave," she says, adding that she was familiar with the warm winds (also known as loo in Urdu) and the precautions that need to be taken in case of one.
"But this phenomenon was quite different — there was no wind, no breeze."
"Death is never easy to experience, but that day, there was a feeling of utter helplessness," recalls Daisy Nasreen, the head nurse at JPMC.
"After we ran out of stretchers, we had to put the dead on the floor. We asked the Edhi Foundation to take away the corpses, but they said their ambulances were busy bringing in those who were still alive. They didn't have any more space in the (Edhi) morgue to take the dead and keep them," she says.
"It was a horrible, horrible, week."
Times of climate change
According to PMD Director General (DG) Ghulam Rasul, heatwaves are going to be "persistent, intense and will go on for longer duration".
A study published last year in the Nature Climate Change journal revealed that the frequency of "lethal" heatwaves will increase across the world. The study further found that heatwaves will be worse at the tropics than at higher latitudes.
Speaking about the heat spell in 2015, Rasul says Karachi had experienced high temperatures (up to 43C) and heatwaves in the past, "but for these to persist for anywhere between four to five days was unprecedented".
On top of that, he says, the high humidity level shot up the heat index level (also known as the 'feels like' factor).
"The urban heat island effect, like the one Karachi experienced three years ago, can become more frequent and pronounced in the future," he warns.
Find out more: Karachi, an 'urban heat island'
When the temperature was 45C, it felt like it had reached 50C (temperatures that are often reported in many parts of Sindh in summer but do not lead to deaths).
This happens because hot air gets trapped and cannot escape like in an oven that does not let the heat escape.
And when it is hot and humid outside, the human body heat cannot expel its heat or perspire and cool off, and a condition called heat toxicity which damages many organs develops.