The world produces a lot of plastic every year. That plastic usually finds it way to landfills. Some of it even lands in our oceans. According to World Watch, the world produces 299 million tons of plastic per year. If you live in Asia, the amount of plastic used by a single person is 20 kilograms per year. Needless to say, there is a lot of polyethylene being used and discarded every day. But once it's discarded, it doesn't serve many purposes. Science fiction kind of changed that when Doc Brown chucked some garbage into his fuel tank in the end of the first Back to the Future movie and powered his vehicle with enough fuel to blast him and Marty McFly into the future. Oh, imagine that, chemical engineers!
The Shangai Institute of Organic Chemistry and the University of California have reportedly developed "efficient and selective degradation of polyethylenes into liquid fuels". The researchers are cognizant of the methods used to produce fuels from plastic today. They, however, say that those methods are low-energy and are not efficient. Additionally, the burning of plastic contributes to harmful emissions. Converting plastic waste into fuel, without creating fossil fuels would be a step forward for 
the world.
The researchers created a process called cross alkane metathesis (CAM). The researchers split the properties of the already manufactured plastic and were left with Ir-H2. They say that splitting of the plastic's properties can then be used with further cross alkane metathesis to produce hydrocarbons that can be used as diesel fuel that is "suitable for transportation". The researchers say the process is highly efficient and inexpensive.
The research implies that plastic and bottles and grocery store plastic bag might be able to be used to make liquid fuel. And we have a lot of those in the world today. You can read the researchers' published works in the Science Advances journal. Their contribution to the journal is titled: Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions.
