De or het ecoplanologie?

The correct Dutch article is:

de ecoplanologie

Rule Words ending in -logie: always de. See the rule
Meaning (Dutch) milieuplanning

How to use ecoplanologie

the ecoplanologiede ecoplanologie
this ecoplanologiedeze ecoplanologie
that ecoplanologiedie ecoplanologie
our ecoplanologieonze ecoplanologie
your ecoplanologiejouw ecoplanologie
every ecoplanologieelke ecoplanologie
which ecoplanologie?welke ecoplanologie?
a big ecoplanologie / the big ecoplanologieeen grote ecoplanologie, de grote ecoplanologie

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).