Learn Danish: Det antages at boligmarkedet falder i år. - It is assumed that the housing market will fall this year.

The impersonal pronoun det (it) acts as a dummy subject for the passive verb antages (is assumed). When paired with an at-clause (that-clause) as it is here, this structure is perfectly suited for expressing general beliefs, estimates, or consensus without specifying exactly who is doing the assuming.

Could I use the other type of passive and say Det bliver antaget at...?

You can, and it is grammatically correct, but the s-passive (antages) is significantly more common in formal, fixed impersonal expressions like this. Using the bliver passive would sound a bit heavier and could imply an ongoing process of people actively making the assumption right now, rather than an established consensus.

The English translation says "will fall," but falder is in the present tense. Why isn't a future tense used?

Danish frequently uses the simple present tense to express future events. Because the sentence includes the time marker i år (this year), the future context is already perfectly clear. While you could technically say vil falde, sticking to the present tense falder is much more natural and concise.

Why is "this year" translated as i år rather than dette år?