At least 15,295 idols, including 213 of Goddess Gauri, were immersed across Mumbai on the seventh day of the Ganesha festival, a BMC official said on Friday. Of the count, 6,818 were immersed in artificial ponds, created to avoid crowding at natural water bodies. No untoward incident was reported. The 10-day festival is being celebrated in low-key manner amid COVID-19.