The Employees' State Insurance (ESI) Act, 1948, is a comprehensive social security legislation designed to protect the interests of workers in cases of sickness, maternity, disablement, and employment injury. The Act has been extended to various establishments over time through notifications. Initially applicable to factories, its coverage has been gradually expanded to include a wide range of non-factory establishments, such as shops, hotels, restaurants, cinemas, road motor transport undertakings, and private medical institutions, subject to certain conditions like the number of employees.