The subordinate clause is : " which had been dumped into the city water system "
Amul is playing a game on his mobile.
Or
Amul played a game on his mobile.
Hopes this helps
Answer:
The name Hopi is a shortened form of their autonym, Hopituh Shi-nu-mu ("The Peaceful People" or "Peaceful Little Ones").
Definition of Hopi: A member of a Pueblo people living chiefly in northeastern Arizona.