Different singing styles include art music such as opera and Chinese opera, Indian music and religious music styles such as gospel, traditional music styles, world music, jazz, blues, ghazal and popular music styles such as pop, rock and electronic dance music.Singing can be formal or informal, arranged, or improvised. It may be done as a form of religious devotion, as a hobby, as a source of pleasure, comfort, or ritual as part of music education or as a profession. Excellence in singing requires time, dedication, instruction, and regular practice.