In case you find yourself in China without a quest to complete, it´s necessary to check the City (Digjong) or the Temple of the 5 Dragons.
When playing the pc version of the game, please go to Map Manager and you´ll see the Digjong city instantly.

In case you didn´t find the new quest in the City, it´s necessary to look in the Temple of the 5 Dragons. Please click on the Main tab and you´ll be able to access the Temple of the 5 Dragons from there.

The interface for the app version is a bit different, however, the idea is the same. In case you´re not able to continue in the game and you need more quests, first, check the City by tapping on the city icon:

In case you won´t find a new quest in the city, please go to Map Manager, tab China. and check the Temple of the 5 Dragons. It´s located among the locations of the Dragon of Wood. Therefore, in case you´re further in the game, you might need to swipe to the right a bit. The icon of the Temple of the 5 Dragons is different than the others so it should be easy to recognize it.

Hopefully, this will help you guys 🙂 Good luck!
In case you´re having issues finding a new quest in Egypt, please check this article.
If you´re having issues finding new quests in Scandinavia, please see this.
To be able to get more quests in Atlantis, make sure to visit this link.
In order to get more quest in Greece, please check the following article.
And if you´re in need of more quests in the New World, please check the steps here.