You have to go back into history. We are as a people corrupt because throughout our societies we have a lot of preference to creature comforts that are sometimes considered a given in the west. Let me be clear, there is also corruption in the west but its on a very deep and more sophisticated level due to the general effectiveness of agencies looking to combat it.How did we become so corrupt (we as in S. Asians in particular)? We started with so much promise - You with Jinnah and we with Gandhi - Nehru duo but somewhere along the line rot set in. Has to be cultural as all three (India, BD and Pakistan) have followed similar trajectories
Corruption is there all over the world but here it is without an iota of shame which accompanies it. In India no one even bats an eye when monstrous sums such as 1 Lakh crore, 2 Lakh crore etc are bandied about.
In our case, the idea of corruption was put into our society early on by the British. They preyed upon the existing culture of "gifts" and nepotism to get their way. We merely refined those approaches and considered them as normal practice.
But the biggest hurdle is lack of education , or rather lack of moral education. We consider corruption as bad but lack the motivation and ideals of fighting it due to a general lack of fighting for morality and justice in society. That is due to the fact that unlike the west who have moved on in large portions of society in their goals of needs and wants; we are still stuck mostly in food, shelter and water.
For the most part, we as a society on many levels have yet to leave the lower tiers of the pyramid.