Davao City had implemented a ban last June banning food containers made from non-biodegradable plastics and polystyrene products across the city.
One result of this is the ubiquitous use of so-called "oxo-biodegradable" plastic bags as eco-friendly substitutes to the actual plastic bags we've come to know.
Oxo-biodegradable plastics, according to Wikipedia, are plastics added with metal salts to facilitate the rapid degradation of these in the natural environment. Usually, it takes plastics decades or even centuries to degrade into compounds which can in turn be absorbed by the soil. Oxo-biodegradable plastics remedy this since they only take years or months to degrade fully.
However, these plastics are not essentially "eco-friendly", according to the Wikipedia article above. First, there lies the danger of increasing the metal toxicity of a given environment if it be exposed to huge amounts of this kind of plastic. Second, we still have to contend with the issue of these plastics lying around for a long time. Third, the lack of research into these kinds of materials make it, at the moment, difficult to incorporate the same into existing recycle streams.