Complex sentence: In ancient times there were underground bricked tunnels "Karaiz" in the city, which had clean drinking water, it is believed they were constructed by Mughals, unfortunately they are blocked by the city garbage, only remains are left.
Split into simpler sentences: In ancient times there were underground bricked tunnels, "karaiz", in the city, which had clean drinking water. Unfortunately they are blocked by the city garbage, and only remains are left.