Frozen pops are a popular summertime snack. But you wouldn’t want to take a lick from any pictured here. The frozen treats may look yummy if you take a quick glance, but upon closer inspection, you’ll notice that they’re filled with trash and grime.

Students from the National Taiwan University of Arts made the pollution-filled pops to highlight the importance of clean water. They spent two months collecting samples of sewage runoff from 100 locations across Taiwan. Then they froze them into ice pops. The students had to buy a separate freezer for the project because the pops smelled so terrible.

Since the ice pops would melt outside of a freezer, the students decided to make replicas to put on display instead. They gathered bits of trash that looked like what they saw in their original ice pops. Then the young artists embedded the litter in a thick, gluelike substance called resin, which they had poured into ice pop molds. The resin hardened into identical-looking fake pops. The students even created packaging for the gross treats. Each had a wrapper labeled with the name of the place where the dirty water had originally been collected.

During the project, the students discovered that plastic made up 90 percent of the waste found in their samples. Each year, millions of tons of plastic trash ends up in storm drains and waterways—and eventually, in the ocean.