I have heard that one can actively go to the polling booth and not vote for any candidate. If such votes exceed the number of votes of the leading candidate, then the election is automatically countermanded.
It was an option during the paper ballot days to deliberately invalidate your vote. It is possible that this one though may be existing in law has been quietly removed when turning the voting process into an electronic one. With the current dissatisfaction against politicians but at the same time no alternative emerging, this is an option that people can exercise. Can someone who knows the constitution well confirm that such an option exists or at least existed during the paper voting times ? regards, Samir