The Sixers' new arena would be build on the western third of the Fashion District mall in Center City Philadelphia, just outside of Chinatown.

Mayor Cherelle Parker is backing the Sixers $1.5 billion arena plan in Center City. Why it matters: Parker's blessing is critical for the stalled project to overcome strong opposition and sends a powerful signal to fellow Democratic lawmakers to fall in line.

Activists rallied outside City Hall to oppose the $1.55 billion plan that aims to build a new venue near Chinatown.