High-resolution, physics-based environmental digital twins
for urban resilience.
Buildings, terrain, streets
Earth observation · Ground sensors · Weather forecasts
Physics + ML · past, present and forecast
Comfort and safety
NO2 · PM2.5 · PM10 · O3
Thermal comfort · heat risk
Exposure and comfort
Buildings, terrain, streets
Earth observation · Ground sensors · Weather forecasts
Physics + ML · past, present and forecast
Wind
Air
Temperature
NoiseSoon
CLARA data flows where it's needed: to data platforms, to administrations and to citizens.
Stream high-resolution environmental data straight into smart-city, real-estate, news, HORECA and other data platforms.
A web platform built for local administrations.
First application
BrusAir was developed for the Smart City program of the City of Brussels and has been live since June 2025, providing high-resolution air quality data to city administrators and citizens.
brusair.be// one call per listing
GET api.clara.city/v1/historical/stats
?address=Chaussée de Waterloo 182, Ixelles
{
"air": { "no2": "...", "pm25": "..." },
"wind": { "comfort": "...", "gusts": "..." },
"thermal": { "utci": "...", "heat": "..." }
}
// air quality, wind and heat
// at the address, from years of data
Property portals plug CLARA into their pages through the API. Each listing gets an environmental report: air quality, wind and temperature at the address, built on years of hyper-local data.
The agent said it was a great location. The report showed the balcony sits in a pollution hotspot. We kept looking.
During a heat wave, the city's resilience team uses CLARA-web to find the streets and squares that overheat, compare them with previous summers, and test where trees or shading would help the most.
We see the thermal hotspots street by street, and we can show why we intervene on one square and not on another.
The mobility department is considering a school street. In CLARA-web they see how traffic pollution gathers around the school at drop-off time, and compare air quality before and after the change, street by street.
We could show parents the difference the school street makes, with data from their own street, not a city average.
This video was produced with the assistance of AI tools.
Everyday Sara commutes from home to work using her bike. Weather conditions can be harsh in Brussels and wind conditions dangerous.
CLARA shows me exactly which streets are shielded from the wind. I can ride home safely!
This video was produced with the assistance of AI tools.
Adam uses CLARA to optimize staffing levels and stay ahead of weather risks, ensuring a safe and comfortable experience on the terrace.
If the app predicts high wind on our street at 19:00, I cancel the extra waiters. I also get alerts to close the parasols before a gust hits. It saves me money and protects my clients.
This video was produced with the assistance of AI tools.
In her classroom, everyday Olivia used to guess when to open the windows. With CLARA, she can see exactly when the air outside is clean.
I ventilate at the right moment and keep my pupils safe from traffic pollution.
Starting from a 3D model of a city, CLARA ingests live data from Earth observation, ground sensors and weather forecasting services into its urban physics simulator based on Computational Fluid Dynamics, accelerated with machine learning, to deliver fast and accurate digital twins of the urban environment: wind, air quality, temperature and, soon, noise.
Cities need this level of detail because conditions change from one street to the next. A building corner turns a breeze into dangerous gusts, a street canyon holds traffic pollution while the avenue nearby stays clean, and a paved square can run several degrees hotter than a shaded courtyard around the corner. Data averaged over a whole neighbourhood misses all of this, and with it the answers people and administrations actually need: which route, which square, which building.
Standard tools stop well before the street. Regional air quality models work at resolutions of a hundred meters to several kilometers1, the weather models behind consumer wind and temperature forecasts at 1 kilometer or more2, satellite observations at a hundred meters to several kilometers3, and official noise maps are static documents, redrawn every few years4. CLARA resolves the city at 1 meter, street by street, building by building, across all of its layers.
Accuracy is the other difference. Most alternative services spread sensor readings over the map with simplified statistical models, or rely on data alone. CLARA works the other way around: its engine solves the fundamental laws of physics (wind motion, pollutant dispersion, heat transfer) on hundreds of millions of computational cells, and uses sensor and satellite data to estimate what the physics alone cannot know. Being physics based makes CLARA accurate in places where no sensor exists, and predictive in conditions that have never been measured, including scenarios that have not happened yet.
1. For example, the Copernicus CAMS European air quality ensemble runs at about 10 km (atmosphere.copernicus.eu), and interpolation-based national services such as RIO in Belgium at 4 km (Janssen et al. 2008, Atmospheric Environment).
2. For example, the global ECMWF IFS-HRES model runs at about 9 km (ecmwf.int), and high-resolution national models such as AROME at 1.3 km (Météo-France).
3. For example, Sentinel-5P TROPOMI resolves NO2 at 5.5 x 3.5 km (Veefkind et al. 2012, Remote Sensing of Environment), and Landsat thermal imagery resolves surface temperature at about 100 m (NASA Landsat).
4. Strategic noise maps under EU Directive 2002/49/EC are reviewed every five years (Environmental Noise Directive).
We generate the digital twin of your territory, you get the dashboards: heat, wind, air quality and soon noise, at 1-meter resolution. The City of Brussels already uses this technology through BrusAir. We can prepare a demo on your own municipality, with no commitment.
Currently in testing, free for everyone in June 2026.
Swipe to explore
CLARA is built on peer-reviewed research by our team and its academic partners, and its predictions are checked against field measurements and reference solutions. Both the validation report and the publications behind the engine are public.
Validation CLARA
Release 2026
Average
Accuracy
Currently in testing. Releasing to the general public, entirely free of charge, in June 2026.
Web-based platform for local administrations. City-scale dashboards, decision support and analytics.
Noise joins wind, air quality and temperature: on the API in September, in the CLARA-app in October.
From 3 covered cities at the end of 2026 to 9 by the end of 2027 and 21 by the end of 2028.
Capabilities currently in development.
Urban Microclimate Adaptation Tool
Test urban adaptation strategies (greening, materials, shading) and assess renewable energy potential.
City Urban Resilience Assistant
An AI layer that interprets CLARA's high-resolution environmental data and suggests urban adaptation strategies.
Disaster and dual-use applications
High-resolution environmental prediction for emergency response, civil protection and dual-use scenarios.
Ask CLARA
Questions about the app, the web platform or the API, answered from this site.
Hello! Ask me anything about CLARA.
Answers can be wrong. For anything important, write to [email protected].