China classifies cities by tier:
一线城市 (Tier 1: Beijing, Shanghai, Guangzhou, Shenzhen),
新一线 (New Tier 1, e.g. Chengdu, Hangzhou), down to
五线 (Tier 5). Generally
大城市 in conversation refers to
一线 and
新一线 — places with rich job markets but punishing housing costs.
