India is home to 22 of the world’s 30 most polluted cities, contributing to high levels of lung and heart disease. Growing up in Mumbai, Angad Daryani experienced the negative health consequences of smog in the form of childhood asthma. Seeking a solution, he came up with the idea to take soot and other polluting particles and turn them into a useful material: building tiles.

While studying at the Georgia Institute of Technology, Daryani came up with an outdoor purification system that removes particles from the air and sucks them into a container. This captured pollution is then given to another company, Carbon Craft Design, which combines it with stone waste from quarries and a binding agent to create floor tiles.

The pollution-capturing devices are 76cm tall and can be mounted onto street lamps, schools, or apartment buildings. They can filter 300 cubic feet of air per minute and store 11,540 cubic centimeters of pollutants. The device doesn’t use a filter, which cuts down on waste and cost, making the cost for two filters $1,830 (135,000 Indian rupees/£1,329). Each filter has a collection chamber to capture the pollutants that need to be emptied out every six months or so, depending on location.

Daryani has recently raised $1.5 million in funding to conduct pilot testing of his filters in schools, hotels, and industrial projects. He is also working on making the devices more affordable so they can be deployed where they are most needed. “Many of the world’s most polluted countries are among the poorest,” Daryani told the BBC. “Poor people work in factories, build the streets and infrastructure, and take public transport to get to work. They live and work in the most polluted environments.”