Columbia subject headings:
Environmental policy--History--Chronology.
Environmental policy--Japan--History--Chronology.
Environmental protection--History--Chronology.
Environmental protection--Japan--History--Chronology.
Japan--Environmental conditions--Chronology.
Harvard subject headings:
Environmental policy--Chronology.
Environmental policy--Japan--Chronology.
Environmental protection--Chronology.
Environmental protection--Japan--Chronology.
Princeton subject headings:
Environmental policy--Chronology.
Environmental policy--Japan--Chronology.
Environmental protection--Chronology.
Environmental protection--Japan--Chronology.