Four Eastern European nations — Bulgaria, Moldava, Romania, and Ukraine — signed an agreement yesterday to increase the protected land in the Danube River delta to more than 2.5 million acres. The Lower Danube Green Corridor, as the protected area will be called, contains wetlands, lakes, meadows, and flood plains. The nations will cooperate in restoring the land, reducing and preventing pollution, and expanding opportunities in the area for fishing and tourism. “Environmental issues have been completely neglected in our countries from behind the Iron Curtain over the past decades,” said Romanian Environment Minister Romica Tomescu. But now the nations want to change course and better protect their natural resources.