100 Rs. per day till the contravention is continous
if the dealer also registered in CST Act than 100 per day for DVAT return as well as CST return (i.e. 200/- per day)
there is no other consequences apart from this but keep in mind this penalty only for late return filling not for late payment of tax. u can submit the penalty challan along with return whenever u file it or at that time of Assessment...