状態・変化N2
〜つつある
in the process of... / gradually...
Structure
V-ます形（語幹）+ つつある
Explanation
Indicates an action or change in progress, common in writing and news reports. Compared with ている, つつある emphasizes the process and direction of the change.
Examples
地球の平均気温は上昇しつつある。
The average temperature of the earth is rising.
彼女は少しずつ回復しつつある。
She is gradually recovering.
Note
More literary than ている; the subject is usually a thing or third person, and it emphasizes an ongoing change.