1) BJP wants to win elections, and with the support of BJP state government's; these blasts may have occured in a p[olitical scenario whre BJP wants to make a point in the coming elections that Cong has not done anything about terrorism.
2) Terrorists interested in unsettling the country. if this is the case: no motive and only revenge. Only targeting pro-hindu governments.
3) Cong trying to prove that BJP although says that they can counterbalance terrorism but there is proof that they failed in their own states.
Now I leave it on you, whatever you want to believe!!!!
In my opinion, these bomb blasts were with a political motive with only 6 months to go for National elections. These were home made low- intensity bombs, which means they were not seriously targetting casualties. This leads us to believe they just want to make a point.
IF these blasts become a political "mudda" in the coming elections, then the one which benefits could be the culprit.