The reason is simple: People feed them. Monkeys are the living representatives of the cherished Hindu god Hanuman, and Hindu tradition calls for feeding monkeys on Tuesdays and Saturdays.

Dr. Tyagi expressed impatience with residents who feed the monkeys one day, then complain to the city when the monkeys steal their clothes on another day…

In 2007, a Delhi deputy mayor died when he fell from his terrace after being attacked by monkeys, a widely publicized episode that spurred the city to step up its efforts to move monkeys to safer environments. Yet such attacks continue. This month a 14-year-old girl was seriously injured when she fell from the roof of a five-story residential building after monkeys pursued her…

Stories abound in Delhi of monkeys’ entering homes, ripping out wiring, stealing clothes and biting those who surprise them. They treat the Indian Parliament building as a playground, have invaded the prime minister’s office and Defense Ministry, sometimes ride buses and subway trains, and chase diplomats from their well-tended gardens.