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NEW DELHI: As Indian cities grapple with severe air pollution and limited green space, scientists have introduced a compact, mobile innovation designed to bring the benefits of photosynthesis directly into crowded urban environments.
Dubbed the Smart Algal Liquid Tree (SALT), this system harnesses microalgae to absorb carbon dioxide and release oxygen, offering a practical alternative where traditional tree planting faces challenges.
How the Liquid Tree Works
At its core, SALT is a contained unit filled with water and microalgae, microscopic organisms highly efficient at photosynthesis.
These algae draw in CO₂ from surrounding air and convert it into oxygen, mimicking the natural process of real trees but in a fraction of the space.
The enclosed design protects the system from urban pollutants, pests, and soil-related issues common in cities.
The device operates continuously, functioning with natural sunlight or artificial light. It incorporates sensors that monitor and display key environmental parameters such as air quality, CO₂ levels, temperature, humidity, and particulate matter. Additional features include dust reduction capabilities.
Mobility and Practical Urban Design
What sets SALT apart from earlier fixed liquid tree concepts is its mobility, allowing deployment wherever needed most.
The unit runs on solar power or electricity, ensuring reliability around the clock. It also serves a dual purpose as public infrastructure, providing shaded seating for four to eight people and equipped with charging ports for mobile phones and laptops.
This multifunctional approach makes it ideal for high-traffic locations such as schools, airports, railway stations, bus terminals, shopping malls, parks, theatres, and industrial zones.
Development and Early Deployments
Researchers at the Council of Scientific and Industrial Research-Central Institute of Mining and Fuel Research (CSIR-CIMFR) in Dhanbad led the project.
Senior principal scientist Vetrivel Anguselvi, who headed the effort, emphasized its targeted application: “The primary purpose of this innovation is to combat poor air quality in densely populated and space-constrained urban areas where there is little or no room to plant large trees.”
The technology has already been installed and tested at the CSIR-CIMFR campus in Dhanbad and at Northern Coalfields Limited (NCL) in Singrauli, Madhya Pradesh, where it has drawn positive responses.
The system is patented, and discussions for commercial production are underway, with efforts focused on making units affordable for broader residential and community use.
India’s rapid urbanization has intensified air quality issues in many cities, where space for large-scale greening is scarce and maintenance of traditional trees can be difficult.
SALT does not aim to replace real trees, which provide biodiversity, shade, cooling, and ecosystem services but to complement them in constrained environments. Its low-maintenance, soil-free design offers resilience in polluted settings.
This development aligns with broader national efforts to leverage biotechnology and clean technology for environmental improvement.
While liquid tree concepts have appeared globally and in some earlier Indian prototypes, SALT stands out as the country’s first mobile version tailored for practical urban deployment.
By integrating air purification with public utility features, SALT could enhance quality of life in polluted hotspots while promoting awareness through its real-time monitoring displays.
Experts see potential for scaling in transport hubs and commercial areas, where it might help mitigate localized pollution peaks.
As commercial rollout progresses, affordability and integration with smart city initiatives will determine its reach. The innovation represents a creative fusion of biology, engineering, and urban planning, demonstrating how science can adapt natural processes to modern challenges.
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