Í borginni er loftið stundum þungt vegna mengunar.

to be

Breakdown of Í borginni er loftið stundum þungt vegna mengunar.

• stundum: sometimes
• í: in
• borgin: the city

Questions & Answers about Í borginni er loftið stundum þungt vegna mengunar.

What does each word in Í borginni er loftið stundum þungt vegna mengunar correspond to in English?

Rough word‑for‑word breakdown:

• Í – in
• borginni – the city (literally city-the in the dative case)
• er – is
• loftið – the air (literally air-the, nominative case)
• stundum – sometimes
• þungt – heavy (neuter form, agreeing with loftið)
• vegna – because of / due to
• mengunar – pollution (genitive case: of pollution)

So the structure is basically: In (the) city is (the) air sometimes heavy because‑of pollution.
Natural English: In the city, the air is sometimes heavy because of pollution.

Why is it borginni and not just borg or borgin?