In the US alone, over 50 billion paper cups end up in landfills each year.
Here's the problem:
Quite simply, traditional paper cups are not designed to be recycled — and recyclers are not set up to process them. These cups are just too difficult to run through their existing paper recycling equipment due to a 100% polyethylene (plastic) coating on the inside of the cup. This coating can't be processed efficiently and would clog their machines — so recyclers simply won't accept this material.