suffix, godan verb (-ru, irregular)
be in the process of doing; be doing
Attaches to the -masu stem of verbs to express an ongoing action or gradual change. Often used in formal or written contexts, and can imply a sense of progression over time.
See also: つつ
地球温暖化は進みつつある。
Global warming is progressing.
新しい技術が開発されつつある。
New technology is being developed.