In Hinduism the stature of an avatar is not bonded by an individual country or geographical boundaries. Kalki Avatar would be much above that, a crusader of truth whose only goal of life would be re-establishing Dharma (righteousness) on mother earth despite all odds.
Representing truth but only truth, this lone crusader of truth would be mounted with jnana wisdom of Bhagavad Gita and also Upanishads (independent spiritual treatises).
Likewise Bhagavad Gita the rule of Kalki Avatar would also be for benefit of entire mankind and not limited to Hinduism only. Correctly stated; in the eyes of Kalki Avatar all living beings, all living forms weighed equal. Even lower forms of life would be given priority in times of need.
If we need killing one duck for our dinner and we land killing three for mere sake of pleasure, then such crimes would not go unnoticed. The sinner would be punished.
Mankind as of today has totally ruined Mother Nature. At each and every stage of physical manifest life we find ethical and moral values taking back seat. Human beings at times reduce themselves to level of animals.
With no reprieve in sight advent of an avatar is the only solution. No sooner Kalki Avatar advents he shall develop a dedicated following of above 2000 million people in a very short time. Another 1000 million people would believe in him.
So much power vested with one single person is what an avatar about in Hinduism.