Complex sentence: A quinquennial election is held to elect corporators to power whose duties are to ensure that their constituencies have the basic civic infrastructure in place and that there is no lacuna on the part of the authorities.
Split into simpler sentences: A quinquennial election is held to elect corporators to power. The corporators are responsible for overseeing that their constituencies have the basic civic infrastructure in place, and that there is no lacuna on the part of the authorities.