FYI, in 1865, when the first NYC subway opened, Manhattan's population density was 35K per square mile. It is now 70K per square mile. Most Chinese cities are like the biggest American cities, ex-NYC, in terms of population density - closer to Long Island than NYC. Shanghai's population density is only 7K per sq mile. Beijing's is 3.4K per sq mile. Bombay and Madras are far more densely populated, with 59K and 69K per sq mile respectively. Again, just FYI.
Shanghai’s only that low-density if you include Jiading, Baoshan, Minhang, and Pudong, all of which have thousands of acres of undeveloped land waiting for more people. AND then tack on the outer suburbs (Songjiang, Fengxian, etc) and the islands (Chongming).
It would be like taking Los Angeles and including all of Ventura County and Riverside County in the density calculation. Yeah, it’s “only an hour” to those areas, but they’re well outside of the urban core.
Get inside Shanghai “proper” (inside the Puxi area - the core 9 districts inside the A20 ring road) which is 281 square kilometers, about 110 square miles, and you’re over 28,000 per square kilometer, which would be about 72,000 per square mile (2.56 square kilometers per square mile).
And I think yesterday nearly all of them were on lines 2 and 9 as I traversed Shanghai...