Siddiqui was working amid the constant hum of machinery when her vision began to blur and her heart started pounding.
The garment factory on the outskirts of Karachi was sweltering, crowded with perspiring workers and large industrial machines radiating heat. The air was heavy with humidity from the summer monsoon.
Feeling as though she could not breathe, Siddiqui drew the concern of her co-workers, who called her supervisor. The 28-year-old, whose identity The Associated Press is withholding beyond her surname for fear of employer retaliation, said she was told to finish her work.
“The supervisor said, ‘Just complete this work,’” she told AP. “Suddenly darkness came before my eyes.”
Overcome by the heat, she collapsed.
Extreme heat, intensified by climate change, is creating hazardous working conditions in Pakistan's factories. From denim jeans to household goods, these factories manufacture products for global companies that have pledged to protect workers' health and safety. However, experts and labour rights advocates say those commitments have yet to translate into adequate workplace protection, leaving workers increasingly vulnerable as temperatures rise.
AP interviewed more than a dozen factory workers in Karachi, all of whom described sweltering workplaces, a lack of heat-safety measures and adverse health effects, including fainting. They spoke on condition of anonymity because they feared retaliation from their employers. All but one said they lost wages when heat-related illnesses forced them to miss work. Ten said they produced goods for global brands sold in the United States and Europe.
Workers face scorching conditions inside factories
For workers like Siddiqui, extreme heat — temperatures of 32.2 degrees Celsius (90 degrees Fahrenheit) or above combined with high humidity — is not merely an occupational hazard.
She lives with her six children in a small room on the outskirts of Karachi without air conditioning, where temperatures regularly exceed 37.8 degrees Celsius (100 degrees Fahrenheit) during heatwaves.
Conditions are even worse inside the garment factory where she sews clothes for Spanish brands such as Zara and Mango. Large machines generate additional heat, while fans are often broken or too small to provide relief. Workers told AP that windows are narrow, positioned high up or kept closed to prevent theft, trapping more heat inside.
“Smoke, heat, you face it,” said a 34-year-old male factory worker.
Heat-related illnesses and wage losses are widespread
Extreme heat can act as a silent killer, sometimes causing little outward indication while inflicting serious internal damage. It can also aggravate existing conditions, including cardiovascular disease, diabetes and asthma. Studies have linked heat exposure to dehydration, heatstroke, organ failure and death.
“The longer you work in the heat, the less that you're protected from it and the health risks rise,” said Andreas Flouris, founder of FAME Lab, which researches the health effects of heat.
Climate change is rapidly increasing the number of people exposed to extreme heat. The World Health Organization identifies heat stress as a leading cause of weather-related deaths. Research by World Weather Attribution has also found that climate change has substantially increased the frequency, intensity and risks of extreme heatwaves in Pakistan.
Workers interviewed by AP reported temporary muscle paralysis, swollen limbs, fluctuations in blood pressure, breathing difficulties, blurred vision and exhaustion, particularly during the hottest months. One worker showed scaly rashes on her arms caused by repeated chemical exposure, saying the pain became worse in summer.
All the workers said they had witnessed colleagues fainting because of the heat. Several had fainted themselves, some on multiple occasions. Those who collapsed were often given only a brief rest or a sugary drink before being instructed to return to work.
Workers said complaints to supervisors had brought no meaningful changes.
Only one worker interviewed by AP said they received paid sick leave. The others said they lost wages for missed working hours, even when they fainted at work or suffered heat-related illnesses.
Siddiqui wept on the floor of her home while recounting how she fainted and was taken to hospital. She earns 15,000 Pakistani rupees ($54) a month, and the cost of hospital treatment — which her employer refused to cover — left her unable to afford food for her children.
“Sometimes they eat one meal, sometimes they don't eat a meal,” she said, adding that her younger children sometimes cry from hunger. “The older ones have gotten used to it.”
Practical solutions remain largely absent
Factories can adopt simple, scalable and economically feasible measures to protect workers from extreme heat, including accurately monitoring indoor temperatures and humidity, providing cold drinking water and allowing regular breaks, Flouris said.
Other measures include installing barriers to reduce radiant heat from machinery, improving ventilation and cooling systems, and painting rooftops white to reflect sunlight.
“We're talking about some very simple strategies,” he said.
However, workers told AP that almost none of these measures were in place at their factories.
Several said the metal roofs of their workplaces made summer conditions unbearable, yet employers did not provide additional drinking water or breaks.
All the workers said their factories lacked heat sensors. Only one reported having a ventilation system, which was switched on only when auditors visited for inspections.
Although employers provided drinking water, workers said it was rarely cold and they were uncertain whether it was safe to drink.
“Sometimes it smells like dead rats,” said the 34-year-old male worker.
Safety pledges by global brands lack enforcement
Pakistan has national and provincial laws, along with constitutional protections, intended to safeguard workers from hazardous workplace conditions, said Farhan Haider, a programme manager at the Pakistan Institute of Labour Education and Research in Karachi.
Some companies sourcing products from these factories, including Inditex, the parent company of Zara, and Mango, have signed legally binding agreements to protect workers or introduced their own workplace safety commitments.
One of the most concrete initiatives is the International Accord for Health and Safety in the Textile and Garment Industry. In 2025, the agreement announced that it would recognise heat as an occupational safety risk and develop protocols to address heat stress. The protocols remain under review and have not yet taken effect.
Representatives of the Pakistan Accord, a country-specific safety programme operating as an extension of the broader International Accord, did not respond to AP's requests for interviews or comment.
Brands have a responsibility to ensure their suppliers are held accountable for protecting workers, including from extreme heat, said Cara Schulte, a researcher at Climate Rights International who published a report on factory workers' conditions in Pakistan in 2025.
In an email to AP, an Inditex spokesperson said the company was strengthening efforts to address heat stress across its supply chain through updated factory audits, guidance and training for suppliers, and cooperation with industry initiatives.
A Mango spokesperson described workers' health and safety as a “non-negotiable priority” and cited the company's supplier code of conduct, which was strengthened this year to explicitly address extreme temperatures and heat stress.
A spokesperson for Sindh province, where Karachi is located, acknowledged that implementation of the regulations remained a challenge.
“The government is making efforts to enforce these regulations, but given the province's vast size and the presence of numerous industrial zones, complaints are inevitable,” said Sadia Javed, who is also a member of the Provincial Assembly.
For workers like Siddiqui, however, complaints continue to go unanswered as temperatures climb.
“If you feel too unwell, (supervisors) say, ‘This is an everyday problem. Women cry and complain a lot, but the work still must be done,’” she said.