Air pollution in India, which has 22 of the world’s 30 most polluted cities, kills more than one million people each year. "You get tired as soon as you wake up because of the pollution," says Angad Daryani. Existing air cleaning technology is large and expensive, so he has created a filterless air purification device that is affordable and small, so it can easily be mounted onto street lamps, apartments and schools. Rather than using filters, which need to be changed daily in a polluted city, his device stores pollutants in a collection chamber that is emptied every two to six months. A single device can catch up to 300 cubic feet of air per minute and store nearly 12,000 cubic centimeters of pollutants. His startup, Praan, recently raised $1.5 million from investors and he hopes to make the device widely available. "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."