NEW DELHI: India has emerged as one of the global hotspots for climate change-driven sleep loss, with residents in cities especially across South India are losing between 78 and 91 hours of sleep annually, of which eight to nine of those hours attributed to climate change.
A new analysis by Climate Central, covering 107 Indian cities, found that Tamil Nadu records the highest climate change-driven sleep loss, with an additional 7.9 hours per person each year.
Rising nighttime temperatures are emerging as a public health threat, with poor sleep linked to cardiovascular disease, poorer mental health, weakened immunity and reduced productivity.
Cities traditionally known for cooler nights, such as Bengaluru and Dehradun, have become warmer, resulting in an additional nine hours of sleep loss over the past five years.
In the 1970s, residents of Bengaluru lost 59 hours of sleep annually. That figure rose to 67 hours in 2025, with the additional eight hours linked to climate change — the highest increase among India's metro cities.
Similarly, sleep loss in Dehradun increased by 10% over the same period.
Globally, the average person lost nearly 56 hours of sleep annually, with more than 10% of that loss attributed to warming caused by climate change between the 1970s and 2025.
The analysis is the first to cover all 1,338 major cities worldwide. It examined rising temperatures caused by the burning of fossil fuels and quantified their impact on sleep using the latest climate attribution science.
The study also found that temperature-related sleep loss attributable to climate change has at least doubled since the early 1970s, with significant implications for public health.
It found that India's metro cities, including Chennai, lost 93 hours of sleep annually, while Mumbai (84 hours) and Kolkata (80 hours) recorded some of the highest overall sleep losses among major metros.
Maharashtra accounted for 22 cities with an average annual sleep loss of 76.3 hours, including 5.8 hours linked to climate change. In Uttar Pradesh's 11 cities, residents lose 69 hours of sleep annually, with 4.9 hours attributable to climate change.
People in cities across the Middle East experienced the highest levels of climate change-attributed sleep loss between 2020 and 2025.
Cities in Saudi Arabia, Oman and the United Arab Emirates lost between 55 and 87 hours of sleep annually because of higher nighttime temperatures, with 12 to 16 of those lost hours attributed to climate change.
Climate change-linked sleep losses were also high in other already hot regions. People in southern India and several countries in Southeast Asia lost between 78 and 91 hours of sleep annually because of higher nighttime temperatures, including about eight to nine hours attributable to climate change.
Similarly, in cities across West Africa, including those in Niger, Nigeria and Burkina Faso, people lost 65 hours of sleep or more each year, including about 10 to 11 hours linked to climate change.