The current game in its modern form originated in Manipur, a northeastern state in India, and was propagated by officers of the British military in the mid 19th century. It is now popular around the world, with well over 100 member countries in the Federation of International Polo. It is played professionally in 16 countries. It was an Olympic sport from 1900 to 1936.
It is known as the sport of kings. It has become a spectator sport for equestrians and society, often supported by sponsorship
The game is played by two opposing teams with the objective of scoring goals by hitting a small hard ball with a long-handled wooden mallet, and through the opposing team's goal. Each team has four mounted riders, and the game usually lasts one to two hours, divided into periods called chukkas (or "chukkers").
Arena polo has similar rules, and is played with three players per team. The playing area is smaller, enclosed, and usually of compacted sand or fine aggregate, often indoors. Arena polo has more maneuvering due to space limitations, and uses an air inflated ball, slightly larger than the hard field polo ball. Standard mallets are used, though slightly larger head arena mallets are an option.
According to Wikipedia