if we say that all the parties are fielding criminals we have solution, go to polling booth & if you don't find any candidate suitable then you can give "no vote" (give it in written to election officer at that booth).if the nos of "no vote" is greater than the margin of votes between the winner & his/her nearest looser then election at that constituency will stand cancelled.from the very next time the parties will fear to field criminals.this is the power of voting.it is written in our constitution (art 49-0).so all are requested to relize the power of your vote & essentially vote to save our country. i request all to grow awareness about your power & spread knowledge amongst others who are not well aware & easily cheated by corrupt netas.