Solution to Pollution
Pollution is a big problem in Tokyo because of the amount of people and industrial buildings. The government of Japan is already working on reducing air pollution by making more green space (parks and the like) around Tokyo. Air pollution is the biggest problem in Tokyo and I think that more trees should be planted and more green space should be made. Alternatively Tokyo could reduce its carbon footprint by making new ways to replace old machines and factories for new eco-friendly machines and buildings.
Solution to Housing
Housing is a large problem in Tokyo because of job opportunities. If there were more job opportunities on the outskirts of Tokyo then people would want to live there. If smaller cities were established on the edge of Tokyo people would want to live there because of jobs and better housing. Tokyo is constantly reaching for the skies and thus requires better construction and less space.