Interest on interest on tds late payments

Hi, Income tax department is sending intimation u/s 200A along with notice of demand in case of late payments of TDS.

I have come across instances where the amount paid/credited on which TDS was deductible was paid/ credited on 31st march where the time limit is 31st may for PY 2009-10. Also the department is charging interest on interest. I would like to know the section under which interest on interest is chargeable and the rate and method of calculation.