Company is an artificial person exists only in eyes of law. In case of private company, 2 or more persons can register a company under companies Act with minimum paid up capital of Rs. 1,00,000 to avoid the mal-practice of establishment of Shell companies. and in case of public company 7 or more persons are required to constitute it.
Where a factory is carrying a MANUFACTURING PROCESS by 10 or more persons with the aid of power and 20 or more without the aid of power.
A company is only created under Compaies Act, 1956 , not under any other Act . e.g. societies Act, Factories Act. so to sue a company filing of complaint must be under the ambit of companies Act.