It’s too bad they don’t provide a link with insight into the metrics used, instead just give an overview – I’d guess that Chengdu outscored most/all the other big cities in terms of water quality.. as for air quality, at least currently, we’re definitely worse off than lots of other major cities according to AQI statistics.
Your reasons for ‘small town feel’ and ‘big city opportunities’ is quite true too. I really think the biggest problem I have with Chengdu now, is air pollution..