Oyo, a start-up that offers budget hotel rooms, has grown into one of India’s most valuable private companies and aims to be the world’s largest hotel chain by 2023. But at least part of Oyo’s rise in India was built on practices that raise questions about the health of its business, according to financial filings, court documents and interviews with 20 current and former employees, as well as others familiar with the start-up’s operations. Many spoke on the condition of anonymity for fear of retaliation from the company. Oyo offers rooms from unavailable ...