The Emperor and the Empress on Monday went to the opening session of Acid Rain 2000, the sixth International Conference on Acidic Deposition.
"This is a problem without country borders, a global issue that it is mandatory for specialists from different parts of the world to collaborate on," the Emperor said in a speech to open the conference at the Tsukuba International Congress Center here.
The acid rain conference was inaugurated in the United States in 1975 to promote research on the causes of and find solutions to environmental problems caused by acid rain.