1. The Mail Bag with your parcel inside is trying to get a place on an Aircraft to get out of China. But unfortunately there is no room for the Mail Bag to get aboard the Aircraft.

2. Just keep tracking your parcel until you don't see anymore tracking for 6 or 7 days, then your parcel would have made it to the Aircraft and left China.

Hope this help.

1. May I suggest you read this:
Mail priority and volume:
If there is more mail than available space to send it, items of higher priority win out over lower ones. As a rule, express lettermail is the highest priority, followed by express packets and parcels, then ordinary lettermail, ordinary parcels, and finally SAL. So if you are sending a parcel via registered airmail, but there is a very high volume of EMS shipments that day, there may not be room for your item, and it’ll have to wait for the next flight.

During times of high mail volume, there is likely to be a backlog of shipments waiting to be sent. Your parcel, of course, starts at the back of the queue.

2. It's an extract from this site here:

I can fly to China in 24 hours! Why does a package take weeks?

Hope this help.