NEW DELHI — A dilapidated building and another under construction collapsed in India on Saturday, killing at least 15 people as rescuers searched for dozens more feared trapped.

In New Delhi, a four-story 50-year-old structure toppled in an area inhabited by the poor. The collapse killed at least 11 people and one survivor was being treated in a hospital.

Hours later, a 12-story building under construction collapsed on the outskirts of Chennai, the capital of southern Tamil Nadu state, as heavy rains pounded the area.

Police said 17 construction workers had been pulled out so far and the search was continuing for nearly 30 others. Four of them died in a hospital, said police officer Mansur Ali.

Nearly 300 policemen and fire service workers were working through Saturday night, searching for survivors.

Building collapses are common in India, where high demand for housing and lax regulations have encouraged some builders to cut corners, use substandard materials or add unauthorized extra floors.