De or het drukvermindering?

The correct Dutch article is:

de drukvermindering

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

How to use drukvermindering

the drukverminderingde drukvermindering
this drukverminderingdeze drukvermindering
that drukverminderingdie drukvermindering
our drukverminderingonze drukvermindering
your drukverminderingjouw drukvermindering
every drukverminderingelke drukvermindering
which drukvermindering?welke drukvermindering?
a big drukvermindering / the big drukverminderingeen grote drukvermindering, de grote drukvermindering

Dutch words ending in drukvermindering

werkdrukvermindering

In compound words, the last part decides the article. See the rule