Apple Inc. has lost a trio of pivotal executives in India in recent weeks as it struggles to boost iPhone sales in the world’s fastest-growing major smartphone market, people familiar with the matter say. Apple’s Indian sales team is now undergoing a restructuring, one of the people said. The executive exodus is a symptom of Apple’s persistent malaise in India, where high tariffs inflate the price tags of imported gadgets such as the iPhone and consumers gravitate toward cheaper alternatives from the likes of Xiaomi Corp. and Samsung Electronics Co. Instead, the company resorts to marketing iPhones that are a few generations old and doesn’t manufacture its latest models domestically, thereby incurring import levies.