Hello,
Firstly, unlike in India, it is almost mandatory in the USA that each individual be covered under a health scheme. Whereas in India, it is voluntary, if an individual wishes, he can buy health insurance for himself and his family.
All the more, the almost mandatory coverage in the USA is not just limited to individuals, but to employers too. As such employers need to ensure that all the employees in the firm are covered under a health scheme so long as they are working with them. Also, the employer needs to continue coverage for a defined period even after cessation of employment. But in India, it is voluntary for companies to provide health insurance to employees.