Japanese automakers Toyota and Mazda are considering a comprehensive tie-up in environmentally-friendly technology amid tightening regulations to cut greenhouse gas and tough emerging market competition, a report said Saturday. Under the partnership, Toyota plans to supply fuel cell and plug-in-hybrid technology to Mazda, which has lagged in electric-vehicle technology, the newspaper said. In return, Mazda will consider offering its proprietary “Skyactiv” green technology to Toyota, which it hopes to use to grow its line of fuel-efficient gasoline and diesel vehicles.