New analysis finds that half of the world’s 100 largest cities are now located in regions suffering from high water stress. This means water demand — for both public supply and industry — is close to or exceeding the available supply in these areas. Experts say poorly managed resources and climate breakdown are key contributors to the growing problem.

According to the mapping study, 38 cities are in areas with extremely high water stress, meaning water withdrawals far outpace sustainable replenishment. Researchers and policymakers are increasingly concerned about what this means for millions of residents and urban systems.

📊 Cities Most Affected

The analysis and mapping, conducted by Watershed Investigations with data from satellite observations, identified some of the largest and most economically significant cities facing severe strain.
Notable examples include:

• Beijing, where industrial and residential demand is intense
• Delhi, with growing consumption and limited resources
• Los Angeles, despite its coastal location
• Rio de Janeiro, with infrastructure challenges

In addition, several other major cities are also highly stressed. These include London, Bangkok and Jakarta, where water demand remains high relative to available resources.

💧 Water Stress Explained

Water stress occurs when annual withdrawals for households, businesses and industry approach or exceed the local water supply. In areas under extreme stress, available water is nearly consumed before the end of the year, leaving ecosystems and communities vulnerable to shortages.

Climate change further worsens the problem by altering rainfall patterns and increasing evaporation rates. As a result, cities with growing populations face heightened pressure on already strained water systems.

🛰️ Satellite Data Shows Longer Trends

A separate analysis of NASA satellite data, compiled by scientists at University College London, adds depth to the findings. This work shows how different cities have changed over the past two decades in terms of water availability. For example:

• Cities such as Chennai, Tehran and Zhengzhou have exhibited strong drying trends
• Others like Tokyo, Lagos and Kampala have shown signs of increased wetness

This long-term view helps experts understand not only where water stress is highest today but also how conditions are shifting over time.

📍 Interactive Atlas Tracks Water Trends

The team published an interactive water security atlas showing water stress levels and trends for all 100 cities. This tool allows policymakers, researchers and the public to explore how water availability has changed and where urgent action may be needed.

Experts hope that this data will inform better planning, improved water management and stronger resilience strategies in urban areas around the globe.

💼 Urban Growth and Water Demand

Rising populations and rapid urban expansion are part of the pressure on water systems. As cities grow, so does demand for drinking water, sanitation and industrial use. In many places, infrastructure has not kept up with growth.

Urban water stress also intersects with food production, energy needs and public health. Therefore, governments and city planners face complex challenges as they try to balance supply with growing demand.