Why did britain and russia become involved in a “great game” in central asia?

Russia was afraid of English business and military advances into Central Asia, and England was afraid of Russia adding India to the immense realm that Russia was working in Asia.  

The English Lord Ellenborough began "The Great Game" on January 12, 1830, with a declaration setting up another exchange course from India to Bukhara, utilizing Turkey, Persia, and Afghanistan as a cradle against Russia to keep it from controlling any ports on the Persian Gulf. Then, Russia needed to build up a nonpartisan zone in Afghanistan taking into consideration their utilization of crucial trade courses.  

This brought about a progression of unsuccessful wars for the English to control Afghanistan, Bukhara, and Turkey. The English lost at all four wars.

Britain sought to protect its interests in India and stop Russian expansion.

Explanation:

Britain feared Russia might win control of northern India, and was determined to stop Russia's southward expansion. Both nations sought to increase their influence in the Ottoman Empire, Persia, Afghanistan, and Tibet.

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