しつつある
shitsutsu aru

Godan Verb (ru)
Expression

1. to be doing; to be in the process of doing

つにつれて、天気 てんき次第 しだい悪化 あっかしつつあった。
higa tatsuni tsurete tenkiwa shidaini akka shitsutsu atta.
The weather was getting worse and worse as the day went on.