number of degrees lower than the outside air temperature. IIRC it was about 10F, so probably 6 degrees Celsius or so. So if it was 90F degrees outside, businesses and public buildings weren’t supposed to set their A/C at more than about 79-80F. That’s probably what you felt at PVG.

I lived in Shanghai for several years and suffered through July and August with insufficient A/C in the office due to that dumb regulation. I always had a fan in my office there. I don’t think it applies to private residences, or if it did, we completely ignored it at home.