During the year I had worked with three different employers and none of them deducted any tax from salary paid to me. If all these amounts are clubbed together, my income will exceed the basic exemption limit. Do I have to pay taxes on my own?

Self-assessment tax: aggregate multiple salaries and pay tax, then file the income tax return.

Where a taxpayer receives salary from multiple employers and none deducted tax at source, the separate salaries must be aggregated; if the total exceeds the basic exemption limit the taxpayer must pay self-assessment tax and file a return of income.