Sometime back I had blogged about why corruption was pervasive, arguing that it pays to be corrupt. A newer version of the decision-tree diagram below (please click to blow-up) captures the expectations and deterrents facing officials when they take bribes
A cursory examination of the extant administrative processes on disciplinary action would reveal that each of the probabilities - p, q, r, a, and b - are far closer to zero than one. Given this, the likelihood of the biggest punishment of a person being caught taking bribes and dismissed from service is (p)(q)(r)(a)(b), an infinitesimally small chance. In any case, the administrative processes make establishing a corrupt practice very difficult. And, even when caught, the current processes leave pretty much the whole share of the rents captured by the official in tact. So, given the stakes involved, if you do not mind the infamy and can manage the inquiry process (not very difficult), it clearly pays to be corrupt!