Applicability:
The ESI Act extends to the whole of India. It applies to all factories, including Government factories (excluding seasonal factories), which employ 10 or more employees and carry on a manufacturing process with the aid of power (20 employees where the manufacturing process is carried out without the aid of power). The act can also be extended to shops and establishments. Generally, shops and establishments employing more than 20 employees as defined by the act are covered by the Act.
The act does not apply to Mines covered under the Mines Act, Indian Naval, Military, or Air Forces, Railways running sheds, and Government Factories or establishments whose employees are in receipt of benefits similar or superior to those provided under the Act.
All employees, including casual, temporary, or contract employees drawing wages less than Rs 6500 per month, are covered. Apprentices are not covered.
A factory or establishment to which this Act applies shall continue to be governed by its provisions even if the number of workers employed falls below the specified limit or the manufacturing process therein ceases to be carried on with the aid of power subsequently.
Where a workman is covered under the ESI scheme:
(a) Compensation under the Workmen's Compensation Act cannot be claimed in respect of employment injury.
(b) No benefits can be claimed under the Maternity Benefits Act.
By the above source, I agree with Mr. Mallik.
Regards,
Suraj Varma
Source: [Employment Law In India](http://www.erlaws.com)