interest u/s 30(2) and us 30(3)

sunil (executie) (185 Points)

30 May 2018  
I have received demand notice from sales tax

they charged interest us 30(2) and 30(3)
only I have to pay interest us 30(2)

what is the reason intrest applicable us 30(3)

after assessment fy 2013 2014
I received demand notice my liability is 11800