Hurricane Maria slammed into Puerto Rico in September, devastating the island’s water and power systems and leaving the island’s residents to drink whatever water they can find.

Oxfam and MIT responded. They partnered with the Puerto Rico Science, Technology and Research Trust and the University of Puerto Rico to conduct a hands-on workshop for community leaders and relief workers. They showed them practical techniques for testing the quality of water and making it safe to drink — like how to turn a 2-liter soda bottle into a water filter. Now those trainees are fanning out across the island to show residents how to use the techniques themselves.

Read more and see the photos at oxfamamerica.org