The large-scale evacuation of millions of people living across numerous jurisdictions is a crucial concern for government officials in preparation for the possibility of major flooding in Tokyo, officials and experts say.

As advanced planning will be important in coordinating the movement of such large numbers of people, the central and local governments in the Tokyo area launched a commission in June to consider how many people would actually need to evacuate and where they should go in the event a significant flood hits the capital.

The government says 1.76 million residents live in places below sea level, encompassing an area of 116 square km near Tokyo Bay and along the Edo, Ara and other rivers.