NEW DLEHI: Rising temperatures are posing a significant threat to human health and work productivity, particularly among informal manual labourers.
A new study by the UK based nonprofit Energy and Climate Intelligence Unit (ECIU) has found that Indian farm workers lose nearly 81 working days a year due to heat stress, the highest number of work hours lost among the countries studied.
Migrant labourers from eastern states such as Bihar, Jharkhand, West Bengal and Odisha travel to Delhi and Gurugram for manual work, seeking to supplement their income during the lean agricultural season.
Most are small and marginal farmers who rely on earnings from urban jobs to support farming activities back home.
“Severe heat puts our bodies out of gear,” said Jagganath, a labourer and contractor from eastern Odisha, who was contracted to clean the sewage system in a high income locality of Gurugram before the rainy season.
“What five of us could finish in a week now takes us 12 days because the extreme heat is affecting our work schedule. We generally work during the early hours, but fewer working hours are impacting our income, which we need to support our farming back in the village,” he said while resting under a neem tree in the lane.
Jagganath's experience reflects the growing heat stress that is steadily undermining workers' incomes and health.
He noted that those most affected by rising temperatures are often the least responsible for global emissions, unlike affluent communities and wealthier nations.
The study, titled Heat Stress & UK Food Imports, examined the impact of heat stress on countries supplying food to the UK and assessed the implications for food security.
It found that workers across the countries studied lose an average of 50 working days annually because of heat stress, with losses increasing by four to five hours each year due to climate change.
According to the report, each Indian worker lost 648 working hours in 2024, representing a 52 per cent increase since 1990. Based on an eight hour working day, this translates to 81 working days lost annually.
The report warned that El Niño cycles could further intensify the impact of heat stress on India's agricultural sector and increase risks to food production.
In 2025, extreme weather events were recorded on 331 of the first 334 days of the year, according to an analysis by a Delhi based think tank. These events, including heatwaves, heavy rainfall, floods, landslides and extreme cold, reportedly caused at least 4,419 deaths and widespread crop losses.
The study also cited the effects of heat stress on crop production in 2023. Extreme rainfall in parts of India damaged tomato crops and caused prices to surge by 400 per cent.
At the same time, extreme heat and humidity, conditions made 30 times more likely by climate change, combined with record monsoon rainfall to affect rice production, resulting in domestic food shortages and restrictions on exports.
The report noted that the UK is expected to import food worth £7.4 billion in 2025 from 15 countries, accounting for 11 per cent of its total food imports by value.
These imports include rice, sugar, lentils, nuts, fish, soy for animal feed, fruits and vegetables such as grapes, onions, oranges and peas, as well as coffee, chocolate, wine and tequila.
The countries supplying these products include Brazil, Peru, Colombia, Ecuador, Mexico and Argentina in Latin America; South Africa, Kenya, Egypt, Ghana and Côte d’Ivoire in Africa; and India, Vietnam, Indonesia and Papua New Guinea in Asia.
According to the study, all 15 countries score below 50 on the Notre Dame Global Adaptation Initiative (ND GAIN) Climate Vulnerability Index, indicating significant climate risks and limited adaptive capacity.
Rising temperatures are already placing pressure on agricultural labour forces in these countries, affecting their ability to meet growing global food demand.
Heat stress is emerging as a major global challenge. The International Labour Organisation (ILO) estimates that by 2030, heat stress could reduce global working hours by 2.2 per cent and result in economic losses of $2.4 trillion in global GDP, up from $280 billion in 1995.
As of 2024, around 71 per cent of the global workforce was exposed to excessive heat. The risk was even higher in Asia at 74.7 per cent, the Arab States at 83.6 per cent and Africa at 92.9 per cent. Outdoor workers remain particularly vulnerable because they often lack access to cooling facilities and adequate shade.
Recent years have recorded unprecedented temperatures, with 2025 becoming the third hottest year on record after 2023 and 2024. Global average temperatures continue to rise, with heat records being broken regularly.
The expected strong El Niño event in 2026 could further amplify climate impacts and potentially make 2027 the hottest year on record.
Researchers warned that heat stress is becoming a silent global crisis, disproportionately affecting older adults and people in lower income regions without access to air conditioning.
Its effects increasingly limit routine activities, including walking and household tasks, with the impact having intensified significantly since 1995 as global temperatures continue to rise.
