I disagree with you on this . Radio advertisement have nothing to do with rural or less develop area. Fact is you think people do not listen to radio anymore. Or you might feel people do not listen to radio in urbanized setting. That is not true. A lot of person use the radio while driving to work or traveling from one place to another. I know you can relate. What makes an advert effective is the ability to reach a targeted audience. Hardly is people in a rural setting a target audience for an advert.Radio advertisement is mostly effective in less developed areas where there is no constant power supply because people use the radio as an alternative to listen to mass media. If there is an area with constant electricity a lot of the population will prefer to be watching TV