The correct answer is: "employees working long hours at low pay in unsafe conditions"
The term sweatshop is used to refer to a working place characterized by socially unceptable conditions, where the work undertaken can be unsafe, underpaid or both. In such places people work very extense shifts without overtime payments, the minimum wage regulations are ignored and sometimes, even laws banning child labor are violated.
The International Labour Organization had set certain standards for workplaces, in order to avoid such situations, and undertakes periodic inspections all over the world, to assess compliance.