Any institutionalized competitive endeavor that fulfils one's personal aspirations (sense of achievement and satisfaction) and objective yearnings (popularity and prosperity) would satisfy the criteria for a sport. And, going by this definition, badminton would fit the bill in anybody's mind.
Badminton compares favorably with any sport, certainly with any racket sport, judging by the sheer physical exertion and mental concentration involved. Badminton is one of the fastest racket sports and the fastest racket shot has been recorded in badminton.
The average badminton match may not last as long as a tennis match, but the average time that the shuttle is in play is significantly much longer than the tennis ball. Also, the average badminton rally lasts much longer than in tennis, and the number of shots taken in a second, especially in a game of doubles, is many more than in tennis.
The on-court movements in a game of badminton are also more, with a player completing nearly a mile on the court. Also you are on your toes all the time, constantly changing positions and lunging and exploding in different directions to retrieve and return the ball.
The game also involves intense mental concentration, akin to chess, continually anticipating and pre-empting your opponent's moves. From the health freak's perspective too, badminton is a sport, providing a complete overall workout for the body and mind.
Badminton is certainly the most participation intensive racket game. Over the past decade, badminton has outstripped tennis in terms of increase in popularity, at least in the rest of the world. But this fact is belied by the comparatively miniscule television coverage that the game receives.
The media and the sponsors, apparently, still do not perceive the game as popular. One would expect this attitude to affect the popularity of the game, but in contrast the number of people who are taking to the sport is steadily increasing. To the truly discerning sports fan, the game advertises itself.
The world has realized this, where badminton has grown in popularity by leaps and bounds. This is one game, which is dominated by the non- white people. We don't know if this is one reason why the game is being cold-shouldered in certain countries, where the average fan is still besotted with other sports. Without detracting from the glory of these other games, badminton is, by no means inferior to them.