The main ground on the plea is section 300 of  Cr.P.C. and article 20(2) of constitution of india.  Regarding double jeopardy.  The convicted are been in jail from 1991 to till date.  Moreover the convicted in jail for 11 years for presidential mercy.

They have already undergone 20 years in jail.  the inmates already undergone the alternate punishment of life imprisonment period.  THERE CANNOT BE TWO PUNISHMENT FOR SAME OFFENCE. 

The investigation is silent about the maker of the bomb and the belt used by Dhanu,(who acted as the human bomb).In case the  ongoing probe by the Multi Dimensional Authority happened to fix these accused, it might  add more teeth for the crime. Thogh the criterion of inordinate delay in deciding the mercy plea is a reason for commutaion of tthe death penalty to life sentence, these two factors constittue ground to have a second thought in the execution of the death sentence.

Dear friend,

                     This case is no double jeopardy, the persons have been convicted and the court ruled that they be hanged, but it was they who preferred to appeal to the President for pardon and no where in the law has it been said that the President sholud decide a mercy plea within a particular period of time, even the words "Reasonable Time" has not been used, therefore 11 years delay in deciding the mercy plea still stands good. Thus it was the convicts who decided to take this chance and therefore cannot now complain on it. 

      This is the legal standpoint, but I agree and share your sentiment as a Tamilian.

It is KASAB's blood the Hindutva Brigade is asking for . It is loud and clear. Those people are not interested in Srilankan terrorists as they are not Muslim . By engineering a resolution against death sentence in the Tamil Nadu Assembly both BJP as well as Grand Old Congress has been put on the dock. That's the whole political game . None is interested except their near and dear ones in which way those convicted persons die.It is the politics of Muslim Hate Hate which is causing so much of heart burn in some quarters.

I strongly believe that no state has any right to kill anybody . Death sentence must be deleted from the list of punishments as Judges are also human beings and err is to human.