Difference of total of debit and credit side of the trial balance is transferred to Suspense A/c. Suspense accounts are used when your trial balance is out of balance or when you have an unidentified transaction. The suspense account is a general ledger account that acts as a holding account until the error is discovered or the unknown transaction is identified.
Municipal tax Rs.6000 under dispute is a Contingent liability. Contingent liabilities are liabilities that may be incurred by an entity depending on the outcome of an uncertain future event such as the outcome of a pending lawsuit.