I live near to the center of Sao Paulo, SP - Brazil, the second (as I remember) largest Metropolitan Area of the World.
Sao Paulo is my first (second, third,...) observing site. The sky limiting magnitude is never better than 3, most of the time is worst than 4.
I have a STRONG light pollution and air pollution also.

Geographic coordinates 23º 35' S, 46º 42' W.