In one of Mexico’s most polluted cities, high school students Jesús Martinez, José Elizalde and Fernando Sanchez invent a paint that can remove pollutants from the air, which takes them all the way to the world-famous ISEF science fair.

As the lakes in her hometown of Bangalore, India fill with clouds of chemical foam that drift through the streets, student Sahithi Pingali creates a “citizen science” project that lets anyone measure and share water quality data, propelling her to the renowned ISEF science fair in Los Angeles.