I made this map of House districts, emulating Japan. It was an interesting case study.
I'm not familiar with Japan's parliamentary electoral system, so how exactly would this be malapportionment?
NYC has 6 seats.
Manhattan and Bronx are seats to themselves.
Queens and Brooklyn+SI both have 2 seats.
However, go north of NYC and seats clearly get smaller.
In CA, LA county has 7 seats, about 1.4 million in each one. Compare to NH and Maine, which have two seats each.
While the PR blocks are not malapportioned, the FPTP single-member seats most definitely are.
Another clear example: compare Nevada and Nebraska. NE gets 3 seats with 600k each. NV gets 2 with 1350k each.