The City of Am'balaar existed as a city situated on the river moon orbiting Al'doleem. Darth Vader's actions led to the city's demise, specifically when he ruptured the nearby dam, which caused the entire city to be submerged underwater.
The initial appearance of Am'balaar city occurred in the canon comic Darth Vader (2017) 4, published in 2017, with the writing attributed to Charles Soule and the illustrations created by Giuseppe Camuncoli.