A 21-year-old student in India named Bittu Tabahi cleaned up a dirty river all by himself. The river was full of trash, but he wanted to make it clean again.
all by himself= 誰の助けも借りず、たった一人で
At first, many people laughed at him. Cleaning the river was dangerous for his health, and he did not have much money or special tools. Still, he kept working every day to remove the garbage.
kept working= 手を止めずに作業を続けた
His hard work completely changed the river. Now, the waterway is clean, and his efforts have moved the government to take action.
take action= 問題解決のために行動を起こす