The dilapidated building in congested Bhendi Bazar area in South Mumbai collapsed on Thursday morning. The death toll had reached 24 by evening.
Iqbal Kaskar, who lives in a nearby building, said he was at home and had just woken up when he heard a loud "explosion-like sound", followed by a swirl of dust. "I immediately rushed down," he said.
"We felt our building vibrate," Iqbal Kaskar said, speaking to a Marathi news channel.
Not many people lived on the upper floors, but several workers lived on the ground floor, Iqbal Kaskar said.
It was a residential-cum-commercial building, he added.
The building is located in the Muslim-dominated Pakmodia Street near J J Hospital. It crumbled at around 8.30 am on Thursday. It's not clear if the heavy rains that inundated Mumbai this week led to the collapse.