To celebrate Global Youth Service Day 2017, YES alumni and volunteers from Semarang, Indonesia, were helping the city janitors to clean the streets as well as raising people awareness about environment during Car Free Day Pahlawan Semarang. Beside cleaning and sharing with people, the alumni and volunteers also making a challenge called Environment Troops Challenge, where they asked people who were at the Car Free Day to join. The challenges was pretty simple, yet very effective and interesting. Two people will making a team up as one to clean the streets, and other collect trashes that were lying on the street. The team who’s able to collect the most trash will get a prize. Surprisingly the challenge was a big hit, all of the participant grab a big trash bag and filled it with every single trash they could find in minutes.