The Ministry of Environmental Protection placed Lanzhou 50th out of 86 locations around China (stats for October 22). Lanzhou is on page 3, but as the results are not ranked I copied and pasted into Excel and reordered them.
The cities ranked 25-80 all got a 'good' rating. However, given that Lanzhou is often criticized for its poor air quality, I thought it would be interesting to see which places came below it. Here is a selection of the most well-known (with their ranking in brackets):
Beijing (81) Light pollution
Harbin (86) Light pollution
This is what Lanzhou looks like today: