India/Pakistan - Kashmir
Periodic high-level conflict until 2003, now simmering more quietly. Historic India-Pakistan power politics involved.
Kashmir was always a religious frontier - once part-Jewish, then Buddhist, then part-Hindu, then part-Muslim, it became a principality affiliated to the British Raj. At independence in 1947, when Pakistan and India separated, a political fudge was made, aligning mostly-Muslim Kashmir with India. Then Pakistan attacked Kashmir, then India invaded it, ending in a cease-fire and a country divided by a ‘line of control’. Muslims live in the west, mainly Muslims are ruled by Hindus in the east, and Buddhists live in Ladakh.
Wars took place between India and Pakistan in 1947-48, 1965 and 1989, with ongoing low-level conflict during the 1990s. Recently increasing numbers of Kashmiris have sought independence. The local conflict has been affected by wider geopolitics and the India-Pakistan nuclear arms race - many Muslim terror groups were supported by the Pakistan government and intel service (ISI), used as deniable proxies for Pakistan's opposition to Indian dominance of Kashmir, which itself was intended to be a resource-drain on India. Ceasefire and softening of rivalries in Kashmir in 2003 after near-nuclear confrontation between Pakistan and India. Poverty and poor governance have aroused sympathy for the militants (Naxalites), posing risk of further conflict. Conflict unresolved. Its main danger lies in its being a breeding ground for new fighters and terrorists.
Links:
Reuters Alertnet: Kashmir
Wikipedia: Kashmir Conflict
BBC: India-Pakistan Timeline
BBC: Kashmir Flashpoint
Jammu and Kashmir Government