You may have to add a few more departments to Mr. Abubakkar's list depending on your industry and your individual responsibility. For example, you may have to deal with RTO (if your company owns vehicles), the Labour Welfare Fund Board, BSNL (unless your company relies only on private service providers), Weights and Measures (Metrology Dept. as it is called nowadays) if your company is using weighing platforms, etc., and the Electricity Department.
And, I would not forget the old (and trustworthy) Posts and Telegraphs Department.