Analyst Koichi Nakano of Sophia University, a private university in Tokyo, doubts the opposition can deliver on its pledges.

NPR: Japan's Opposition Party On Verge Of Historic Win

Koichi Nakano of Sophia University in Tokyo points out that Japan's distorted electoral map exaggerates the size of the defeat: the DPJ lost heavily against LDP candidates in depopulated rural areas that are considered to be the opposition's heartland, but which produce a disproportionate number of seats.

ECONOMIST: Japan's upper-house elections

Sophia Xiang Sun, from the University of Cambridge's autism research centre, argued that cutting pollution would be a good idea anyway.

BBC: Autism: Traffic pollution linked, study suggests