In the early 1900s, the British ruled India and were concerned about the increasing population of cobra snakes in Delhi. They offered cash for those who brought forward cobras. The strategy worked well until the people of India started to breed cobras for the reward. When the government became aware of this, they canceled the program. The worthless snakes were then released into the wild. The result was that there were more snakes than before in Delhi. The attempted solution to the problem actually made the situation even worse and brought about a harmful result instead of the intended good one. From the story came the name "cobra effect." Actually, similar sorts of things have happened through history. In 1989, Mexico City introduced a car license-rationing project to combat air pollution. By restricting the cars driving on the road based on the numbers on car plates, they thought it would lead to less car emissions. But the plan backfired. People simply bought a second car to get around the rule. Limiting who could drive on roads didn't lessen air pollution but rather worsened it. The concept delivers an important lesson for policy makers.