China's 'Outdoor AC' Goes Viral As Heatwave Scorches Cities: Here's How It Works

In the peak summer season, the urban heat island effect exacerbates already punishing heatwaves, making apartments in high-rises feel like sealed ovens. Even at night, fans offer little relief as thermometers stubbornly hover above 40 degrees Celsius long after sunset. This trapped heat pushes the 'feels-like' temperature to levels the human body struggles to tolerate. This week, the 'feels-like' temperature in the National Capital Region (NCR) touched 51 degrees Celsius, making life difficult for people living in cities. In such a scenario, a new cooling method - dubbed the "outdoor AC" - is gaining traction on the internet.

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Videos circulating on X and other platforms show dedicated mist cooling systems installed on the terraces of high-rises in China, with claims that they can lower the surrounding temperature by 3-6 degrees Celsius. NDTV cannot vouch for the authenticity of the video.

✨🇨🇳Chinese residential communities feature dedicated mist cooling systems.

Summer activation cuts outdoor heat by 3–6°C for comfy outdoor spaces. pic.twitter.com/NuPrxSE0t9

— 🇨🇳XuZhenqing徐祯卿 (@XueJia24682) June 26, 2026

What is the outdoor mist cooling system?

An outdoor mist cooling system is a technology that cools open or semi-open spaces by spraying an ultra-fine mist of water into the air. It works on the principle of evaporative cooling: tiny water droplets absorb heat from the surrounding air as they evaporate, lowering the ambient temperature by several degrees without soaking people or surfaces when a high-pressure system is used.

Commonly installed in cafes, restaurants, gardens, terraces, warehouses and event venues, these systems are especially useful during hot summers. They consume relatively little electricity and water compared with conventional air conditioning, making them a cost-effective cooling solution for outdoor environments.

Why is it effective in tackling urban heat?

Outdoor mist cooling systems are particularly effective in urban settings because cities experience the urban heat island effect, where concrete buildings, asphalt roads and limited green cover absorb and retain heat, making temperatures several degrees higher than in surrounding rural areas.

In such environments, mist cooling systems help counter the heat by releasing ultra-fine water droplets that evaporate quickly, absorbing heat from the air and creating a cooler microclimate. This makes outdoor spaces such as restaurant patios, public plazas, bus stops, markets and event venues more comfortable during peak summer months while consuming far less energy than conventional air conditioning for open spaces.

The gruelling heat

Summer heat in India can be brutal, and climate change is making extreme heat more common. During a May 2024 heatwave, Delhi matched its previous record high of 49.2 degrees Celsius, first recorded in 2022.

Night-time temperatures are also rising. Last month, the India Meteorological Department (IMD) recorded a minimum temperature of 31.9 degrees Celsius, the city's highest May night-time temperature in 14 years.

Meanwhile, residents in Delhi-NCR woke up to warm and humid conditions on Monday morning amid the delayed arrival of the monsoon.

Residents may soon get relief from the scorching heat as cloudy skies and spells of rain are expected in parts of the region. The IMD has indicated the possibility of showers accompanied by thunderstorms and strong winds in Delhi-NCR as monsoon conditions become more favourable over North India.