A cess imposed by the central government is a tax on tax, levied by the government for a specific purpose. Generally, cess is expected to be levied till the time the government gets enough money for that purpose.
Surcharge is a charge on any tax, charged on the tax already paid. As the name suggests, surcharge is an additional charge or tax. The main surcharges are that on personal income tax (on high income slabs and on super rich) and on corporate inc.
How cess is differ from surcharge?
The main difference between surcharge and cess is that despite they are not shareable with state governments, surcharge can be kept with the CFI and spent like any other taxes, the cess should be kept as a separate fund after allocating to CFI and can be spent only for a specific purpose. This means cess can be spent only for the specific purpose for which it is created. If the purpose for which the cess is created is fulfilled, it should be eliminated.