This is the 902nd most frequent German word.
verbesserung
Improvement.
In this sentence, 'Verbesserung' is used as a noun (female gender with the article 'die') to indicate the process or result of making the infrastructure better.
Die Verbesserung der Infrastruktur war dringend notwendig.
The improvement of the infrastructure was urgently necessary.
Here, 'Verbesserung' is used as a concept of personal development or enhancement of skills.
Er arbeitet an der Verbesserung seiner Sprachfähigkeiten.
He is working on improving his language skills.
In this case, 'Verbesserung' refers to a specific change or addition that has been made to improve something.