Why is interest under 234a applicable to me?

Sanjit (not applicable) (119 Points)

16 March 2015  

I self assessed my income tax and paid the taxes for PY 2013-14 online by on 27/7/14

This brought my self assessed tax liability to zero

I then generated the X M L file and uploaded to my income tax site on 31st  Dec 2014

What exactly did i get chrged the interest for?

I filed ITR 4 as i have income from salary, pofession and other sources

Please tell me by when am i supposed to do these filings ans tax payments to avoid errors in the forthcoming AY

Thanks