どんどん
Usage
どんどん expresses the idea that something proceeds from one stage to another or continues to happen at a fast pace with no delay, or that someone keeps doing something with no hesitation. In some situations both ますます and どんどん can be used. At a fast pace; one after another; keep V-ing vigorously
Examples
「とびら」で勉強するようになって、学生たちは日本語がどんどん上手になってきた。
By learning with Tobira, the students became good at Japanese at a fast pace
地球温暖化のせいで、グリーンランドの氷がどんどん溶けているそうだ。
Due to the the global warning, I heard that Greenland's ice is melting quickly.