A new app is encouraging users to clean up New York City streets.

The game, called EMRALS, was invented by Brooklyn native Sean Auriti. After creating an account, users post pictures to the app of dirty streets or sidewalks. Other users then clean up the spot and post a new picture afterward.

Users are paid in online currency when they clean up the trash in their neighborhoods.

EMRALS is a top 20 finalist in the NYC Big Apps competition that is being sponsored by the city. The winner will be announced Tuesday and will get $20,000 to expand their project.