India ? At least three people have been killed and 10 injured after a six-story building collapsed in the city of Mumbai in western India, a local police source said Monday.

Mumbai, formerly known as Bombay, is the capital of the state of Maharashtra, the most populous city in India, and by some measures the most populous city in the world, with an estimated population of about 13 million.

Unauthorized alteration of buildings, including the addition of upper floors, is a common practice in Mumbai, where the cost of real estate is skyrocketing. Authorities believe it is the main cause of a recent wave of building collapses in the city.

The Monday incident is the fifth reported building collapse in the commercial and entertainment capital of India in more than a month.