The claim:
Sadiq Khan said "most Londoners agree with [him]" about the ULEZ expansion.
Analysis:
This is not true.
Over 60% voted against the ULEZ expansion in the official consultation (source). 80% of outer London businesses were opposed, 80% of outer London workers, 75% of visitors to London, and 90% of black cab drivers.
The latest YouGov polling also shows a clear majority are opposed (Telegraph).