TOKYO (AP) — Japan has a plastic problem.In a country where cleanliness and neat packaging have long been considered good service, almost everything, from single bananas to individual pieces of vegetables, pastries, pens and cosmetics is sold plastic-wrapped. But as world leaders descend on Osaka for the two-day G-20 summit that starts Friday, Japan will attempt to become a leader in environmental policy at the same time it plays catch-up with countries that already have well-defined goals in place. In the months leading up to the G-20 summit, Japanese officials have delivered full-throated endorsements of future bans on single-use plastics, beach cleanup efforts and more research into alternatives such as bioplastics. The problem is, the enforcement and timing of the directives have yet to match measures already in place in the EU — including sweeping legislation passed earlier this year that will ban single-use plastic in all member states by 2021. Just last summer, Japan was criticized for failing to sign the G-7 Plastics Charter, the only country to do so besides the United States. At a mid-June meeting of G-20 environmental ministers in Karuizawa, Japan brokered an agreeme...