If anyone is looking for a good project, alternate Wasserstein distance/EMD solvers would be a good place to start.
AFAIK everyone (eg, pyemd, gensim, textacy) uses wrappers around the EMD solver from http://ofirpele.droppages.com/, which is a zip file from some time in 2008. The limits on performance mean it can't practically be used in things like interactive nearest neighbor calculations (FAISS, nmslib, annoy etc)