India, Aug. 18 -- As the BWF World Championships got underway at Delhi's Indira Gandhi Indoor Stadium on Monday, organisers were determined to avoid a repeat of January's India Open embarrassment. Then, pigeon droppings interrupted play and a monkey wandered into the venue. This time, the stadium has undergone deep cleaning, anti-pest gel has been applied along roof beams to deter pigeons and, most unusually, three men have been hired to mimic langur calls to scare away rhesus monkeys.

"Monkeys are absolutely terrified of langurs, which is why mimicking is so effective. We replicate the warning call of a langur and that has the monkeys run away," says Zafar, one of the mimics. The measures had already made headlines before the tournament...