Originally Posted by GUWonder
It's enough. If you happen to be going to/from DEL, do not try the bribe approach under any circumstances. [There is a sting operation underway.]
Delhi immigration openly asks you for bribes if they decide you are a suitable target. On one occasion, I spent over an hour in a side room at Delhi airport departures (traveling as an Indian citizen on an Indian passport) being shaken down by immigration officers who made it very clear that a "donation" could speed me on my way soon enough. I finally escaped once I mentioned the name of the AI airport manager at the time, an old family friend, who presumably has enough clout to get them in trouble.
Still, Mumbai and most of the other airports in India target mainly the labour traffic to exploit for bribes since they are naive travelers for the most part. Delhi on the other hand brazenly targets anybody. Swinging a posting to Delhi airport is one of the most expensive "donations" for immigration officers anyway, so this is their only way of recouping costs.
As for "sting operations", that is simply another way to shake down the poor travelers who get caught up in the web. Catch the guy red handed paying the requested bribe and you can extort even more from him.