The report, Too Hot to Ignore: Extreme Heat in Garment Supply Chains, finds that rising temperatures and humidity are reducing productivity, affecting product quality, and threatening delivery schedules in some of the world’s key garment-producing regions.
Despite these issues, the study reveals that most global fashion brands do not require their suppliers to collect basic temperature or humidity data at the factory level.
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The report is based on field research at 10 garment facilities across four regions of India, interviews with about 120 workers and management, factory medical-room data, and a survey of major apparel and footwear brands. It outlines how higher temperatures and humidity have led to measurable declines in factory output and workforce attendance.
According to the survey, 94.1% of apparel and footwear brands identified extreme heat as posing a moderate or significant risk to production. Still, only 35.3% ask suppliers to monitor indoor temperature or humidity, and none were found to collect this data continuously.
NYU Stern Center for Business and Human Rights global labour senior research scientist Lucy Siers said: “Extreme heat is now a predictable supply chain risk for apparel brands. Factories are losing output, quality is suffering, and delivery timelines are at risk, not as a future scenario, but right now. Brands that require heat monitoring, adjust purchasing practices, and share the cost of adaptation will build more resilient supply chains. Brands that continue to treat heat as someone else’s operational problem are taking on risks they cannot see.”
Key findings from the report
Factory managers interviewed described a range of problems linked to heat. Managers in nine factories reported productivity reductions of roughly 3% to 10% during peak summer months, and absenteeism increases of about 2% to 5%.
Heat contributed to sweat stains on fabric, dust contamination, errors in stitching, equipment overheating, and, at times, forced halts in production.
The report also revealed that workers’ experiences of dizziness, headaches, dehydration, fainting, skin rashes, kidney and urinary issues, and higher medical costs during the hottest months.
Indoor temperatures recorded at one dyeing and processing facility reached up to 45°C, surpassing already hazardous outside temperatures by as much as 5°C.
Practical responses to heat were found to be possible, but were largely funded by suppliers themselves. In Tamil Nadu, targeted cooling measures reportedly lowered factory temperatures by 2–3°C and cut absenteeism in summer from about 12% to around 7%. Suppliers indicated to NYU Stern that further investment in heat mitigation is dependent on brand requirements, technical support, or financial partnership.
The NYU Stern Center points to Epic Group’s Bhubaneswar facility as an example, where close collaboration between the brand, supplier, and IFC financing has resulted in a factory that keeps temperatures at about 28°C through passive cooling, automated systems, and high-volume fans.
According to the report, this demonstrates how early partnership on climate adaptation can create workplaces better equipped to manage extreme heat.
NYU Stern Center for Business and Human Rights director Michael Posner added: “Brands that source from heat-exposed regions have both a business interest and a responsibility to act. The answer is not to walk away from these sourcing regions and leave workers and suppliers behind. It is to invest in making them more resilient by requiring heat monitoring, setting clear safety standards, building flexibility into purchasing practices when heat disrupts production, and sharing the cost of cooling and ventilation upgrades.”
Key recommendations
- Require continuous heat monitoring: Brands should ensure suppliers track temperature and humidity inside factories throughout the year to spot unsafe conditions and address issues before they affect workers or production.
- Establish enforceable heat-safety rules: Brands are advised to set strict temperature and humidity limits with suppliers, triggering measures like rest breaks, cooled rest areas, or production pauses when conditions become hazardous.
- Integrate heat risk into planning: Adjusting lead times and targets can help brands and suppliers adapt to predictable heat-related disruptions.
- Support investment in cooling: Brands, governments, and financial partners should help pay for upgrades such as cooling systems and improved ventilation.
- Coordinate company-wide: Teams across sourcing, procurement, sustainability, and supply chain management should work together to align commercial practices with worker protection and supply chain resilience.
