India is among the global hotspots for climate-related sleep loss with people in southern parts of the country losing 78 to 91 hours of sleep annually, including eight to nine hours due to climate change, according to a new report by Climate Central.The findings add to growing evidence that climate change is not only causing extreme weather events but is also affecting everyday aspects of life, including how well people sleep.The report analysed temperature data and sleep research from 1,338 major cities worldwide, including 107 cities in India. Researchers found that across all cities studied, climate change has at least doubled heat-related sleep loss since the early 1970s.Globally, an average person lost nearly 56 hours of sleep every year because of night-time heat between 2020 and 2025. Around six of those lost hours were directly linked to climate change, accounting for just over 10 per cent of the total sleep loss.However, the impact is much greater in places where nights are already very warm, including several parts of India.Among Indian states, Tamil Nadu recorded the highest climate change-driven sleep loss, with residents losing an estimated 7.9 additional hours of sleep per person each year due to climate change. Chennai recorded the highest overall sleep loss at 93 hours per year.Mumbai followed with 84 hours. Kolkata recorded 80 hours of sleep loss annually. Bengaluru showed the strongest climate change signal, with around eight hours of sleep loss every year directly linked to climate change.“In Maharashtra, around 76.3 hours of sleep was lost annually, including 5.8 hours due to climate change. Around 69 hours of sleep was lost each year in Uttar Pradesh, with 4.9 hours attributed to climate change,” the report noted.The human body naturally lowers its core temperature before and during sleep. Cooler night-time temperatures help this process and allow the body to enter deeper, more restorative stages of sleep.When nights remain hot, the body struggles to cool itself. This makes it harder to fall asleep, increases the chances of waking up during the night and reduces the amount of deep sleep a person gets. Even if someone spends enough time in bed, the quality of sleep may be poor.Unlike daytime heat, night-time heat often goes unnoticed because people are indoors. However, experts say it may have long-term health consequences.Kristina Dahl, Vice-President for Science at Climate Central, said the report demonstrates another hidden cost of global warming.She said the analysis shows that climate change is translating into measurable hours of lost sleep by combining climate attribution science with research on how heat affects sleep.According to Dahl, climate change has at least doubled temperature-related sleep loss across more than 1,300 cities since the early 1970s, highlighting that the effects of fossil fuel-driven warming extend beyond extreme weather and affect one of the most basic human needs.The report says hotter nights are becoming more common as climate change continues to warm the planet. While extreme heat often receives attention because of heatwaves and record-breaking daytime temperatures, rising night-time temperatures could become an equally important public health challenge.