I encountered an area today with a “no loading” condition a specific time periods. I expect the time part to be fairly standard but while clearways and other “no stopping” zones are normally handled by (ab)use of the parking condition tags, I can’t see anything for loading restrictions (only permissions).
I think we must have something for this, but I can only find issues with loading in the internet sense in my search of the help site.
There is a lane conditional . https://wiki.openstreetmap.org/wiki/Key:motor_vehicle You should be to use it to construct a “no @ delivery”. If understand the keyword correctly this should mean that no one can stop there for the purpose of un/loading things in/out of their motor vehicle.
Are you referring to parking:condition=no_stopping for clearways? I believe that’s the intended use case for that tag, following this recent successful proposal. It’s possible to distinguish between clearways and other “no stopping” or “no standing” restrictions using parking:condition:reason. Is there another representation that you consider to be more correct?
Some parts of it are double yellow lines but the rest are just kerb stripes so presumably in the non-double yellow bits you can stop as long as you aren’t loading unloading.
It’s actually in the vicinity of a school with the restrictions during peak dropoff/collection times. I wouldn’t have thought that no loading actually applies to passengers but if it doesn’t the whole thing seems rather pointless.
If they don’t want anyone to park, i would use the mentioned no_stopping keywod. Though that might make it illegal for parents to drop-off/pickup thier kids. I have feeling that school officials don’t want delivering during those times as it would impact student safety. Something like no @ delivery and a set times when student are oit in front of school. This would prevent goods and larger vehicles from conducting thier activities while students are not in class or safely elsewhere on school property.
This reminds me of the 
Passenger Loading Only signs that are often posted around schools in California. But those don’t allow you to stop and loiter if you aren’t loading anything at all. The no @ delivery suggestion sounds correct in this situation.