There are two things all Indians usually agree to -- English the language and Cricket the game. Its rather easy to understand why Indians like to learn and use English as mode of communication -- in a country of hundreds of languages its easier to agree on a neutral language as a mode of communication.
After the World Cup victory in 1983 Cricket has seen an exponential increase in its popularity in India (also in the sub-continent) and emergence of Indian Premier League is a clear sign of Cricket's popularity and emergence of India as a powerhouse of Cricket.
Why Indians started to like Cricket so much? Somehow it does not make sense? A colonial game becoming such a huge success, maybe it has something to do with having a chance to defeat England (particularly in England). But is that all? Most people will agree on it. There is one problem though. Before a population, a country realizes that Cricket is an opportunity to defeat England, the game of Cricket must exist in the public imagination, i.e. a large population should find interest in the game and appreciate it.
Why Indians or for that matter the sub-continent chose Cricket over Soccer? Why a game which potentially takes up days (in its most traditional sense), whose rules (actually they are called Laws) no average person can really fathom. How difficult Cricket is, becomes very evident when you try to explain the game to someone not already familiar with it, say to the Germans. After explaining the basic idea of Cricket, its not easy to find people who would like to know and follow cricket. You essentially have to grow up into an atmosphere filled with it to really appreciate it.
In the following I propose my conjecture why Cricket could capture the imagination of a huge population in India and in the sub-continent and why other sports such as soccer failed to find a niche in the sub-continent. In fact I will use the example of soccer to make the case for the popularity of Cricket.
India is a country of a huge middle class and a equally large number of people live below the poverty line. Those in the middle class are in a strange state, in fact they are in a transition state, as all factors indicate that are just one step before making it to the so called upper-class. So, all their efforts are directed to achieve something in their life, make it big and complete the transition to upper class. Education is traditionally seen as a means to complete the transition.
Kids are asked "what did they do?" instead of "how did they do?" in any thing they do.
If a kid comes home after a game of soccer, his parents and other elders would ask him what did he do in the game? Not all players can score a goal in soccer. But how will you tell this to your parents, for them running around after the soccer ball with other 21, is an utter wasteful activity. It appears that Indian parents want a quantitative measure of the performance of their kids.
Cricket provided them exactly that. After the game of cricket, you can tell your performance in number, 10-2-28-3 or 32 runs, two catches or a run out, or even more mundane but hugely appreciated 3- fours or 2 sixes.
Arguably, cricket is one of the most democratic of all team sports. Physical strength is a not such an important parameter, if you can manage to stand and run every now and then, over five days, it will do. If you cannot bowl fast, you can become a spinner; if you cant hit big shots, you can still be a very effective accumulator of runs. In fact, no other team sport can show so many physically unfit sports-persons in their hall-of-fame. For a country like India, where middle class does not only refer to economical status but it also conforms with the standards of physical strength (excluding perhaps the farmers), cricket emerged as the perfect game for the middle class.
Further, in Cricket when your turn comes to play your part, no one is allowed to disturb you. In soccer for example as soon as you get the ball, at least four other player will come around you to snatch the ball and of course, besides skills, physical strength of the players does influence the outcome. In Cricket on the contrary when you are on the wicket, batting, the laws prohibit even a small whisper from other players. Similarly when you are about to bowl, the opposition players dont come around and distract you right when you are about to release the ball. Ok, sledging happens. This feature necessarily makes it a popular choice among kids who are not physically strong and need to mentally focus to apply their skills.
Sports are traditionally thought to be for the those physically strong. Cricket removes this bias and still provides a quantitative way to measure up the performance. I think these are most defining aspects of Cricket. In my opinion, these two aspects of cricket contributed to the popularity of cricket in middle class and it was a matter of time (about a generation) when India came out of age and is on its way to become a super-power of Cricket.
I think that similar reasons exist for other countries such as Pakistan, Sri-Lanka, Bangladesh and perhaps even in the West-Indies.
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PS: Scalability and flexibility are two necessary things a game needs to become a popular sport. As far as the rule (or Laws) of the game go, they may appear very complicated in an MCC manual. In practice the game is amazingly scalable to any arbitrary number of players and amazingly flexible to bend the laws without altering the spirit of the game.