Short for 共青团市委员会 — the city-level organ of the 共青团 (Communist Youth League, CYL). The CYL is a key political training ground: many senior Party officials, including former President 胡锦涛 and former Premier 李克强, built their careers through it.
usage
Parallel forms: 团中央 (national), 团省委 (provincial), 团县委 (county). The 团 prefix always means 共青团.