noun
improvement work; renovation; betterment
Refers to construction or engineering work aimed at improving existing facilities, infrastructure, or systems. Often used in technical, municipal, or project contexts.
市は来月から公園の改良工事を始める予定だ。
The city plans to start improvement work on the park next month.
この道路の改良工事は来年まで続く。
The improvement work on this road will continue until next year.
Compound of 改良 (improvement) and 工事 (construction work). The exact historical derivation is uncertain, but the term is a straightforward modern technical compound.