Learn Dutch: Het afval is een probleem voor het milieu. - The waste is a problem for the environment.

Both afval (waste) and milieu (environment) are neuter nouns, known as het-words. There isn't a single strict rule for which words get het, though many French loanwords like milieu do. It is best to memorize them together with their article: het afval and het milieu.

How do you pronounce milieu?

Because milieu is borrowed from French, it doesn't follow standard Dutch spelling and pronunciation rules. It is pronounced roughly like mil-YEU (where the eu sounds a bit like the ur in the English word hurt, but shorter and with no r sound).

Is afval the only word for garbage in Dutch?

Afval is a very broad, uncountable word that covers all kinds of waste, trash, or garbage, especially in environmental contexts. You will also frequently hear the word vuilnis, which is typically used for everyday household garbage (like in vuilniszak for garbage bag).

If I want to talk about multiple problems, how do I make probleem plural?

The plural is problemen. Notice that the double ee in probleem changes to a single e. This is because the syllable opens up when you add -en (pro-ble-men), and an open syllable automatically makes the vowel sound long in Dutch without needing the double letter.