Bloomberg claim 256% debt:gdp ratio, but it's hard to collaberate. China doesn't appear on Business Insiders list from 2015 [0], which has Japan at 250%ish. Trading economics [1] has China at 48% government debt:gdp
Household debt isn't that bad either, however the grauniad has the answer -- corporate debt is sky-high [2]. It also mentions that by this measure (Corporate + household + government debt), the U.S. is 331%. It's an interesting article, albeit from 2 years ago
A source for the high debt to GDP ratio? A simple Google search would suffice, but here: https://www.bloomberg.com/news/articles/2018-02-08/sizing-up...