Breakdown of Am Zoll wird streng kontrolliert.
am
on the / at the
streng
strict
werden
to be (passive auxiliary + past participle)
kontrollieren
to inspect
Questions & Answers about Am Zoll wird streng kontrolliert.
Why is there no subject, not even es, in this sentence?
This is the impersonal passive, which focuses entirely on the action happening rather than who is doing it. You could use a dummy subject es if you needed to fill the first position (Es wird am Zoll streng kontrolliert). However, because we put the location (Am Zoll) in position 1, the es drops out completely. The conjugated verb wird still acts like it has a third-person singular subject.
The English translation uses the noun "checks", but German uses a verb. Why?
English often uses "there is/are" plus a noun to describe general situations like "there are strict checks." German prefers to use the impersonal passive of the verb kontrollieren (to check or to inspect). Literally, the German says "At customs, [it] is being strictly checked." This is a very natural way to express general rules, events, or ongoing activities in German without needing to invent a subject.
Why does the sentence use Am instead of An dem or Bei dem?
In German, am is the standard, mandatory contraction of an and dem. You use the dative case (dem) here because an is a two-way preposition answering a "where" question, indicating a fixed location. While beim Zoll is also grammatically correct and means roughly the same thing, am Zoll is the most common way to say you are physically at a border or customs checkpoint.
Why is the verb split into and ?