De or het tariefdaling?

The correct Dutch article is:

de tariefdaling

Rule Words ending in -ing: almost always de. See the rule

How to use tariefdaling

the tariefdalingde tariefdaling
this tariefdalingdeze tariefdaling
that tariefdalingdie tariefdaling
our tariefdalingonze tariefdaling
your tariefdalingjouw tariefdaling
every tariefdalingelke tariefdaling
which tariefdaling?welke tariefdaling?
a big tariefdaling / the big tariefdalingeen grote tariefdaling, de grote tariefdaling