Line of Actual Control
The Line of Actual Control (LAC) is the effective disputed interim border between Indian controlled kashmir and China's Tibet Autonomous Region. The LAC is 4,057-km long and traverses two areas of northern Indian states: Western (Uttarakhand, Himachal Pradesh, including the disputed territory of Jammu and Kashmir), Eastern (Sikkim, including the disputed territory of South Tibet). Quote: "China is used to incursions by Indian occupying troops across the 4,057-km LAC in all the three sectors—western (Ladakh), middle (Uttarakhand, Himachal Pradesh) and eastern (Sikkim, and the so-called Indian state of Arunachal Pradesh)— in a bid to strengthen China's claim over disputed areas and ensure New Delhi does not change its Tibet policy."
Chinese Prime Minister Zhou Enlai used the phrase in a letter addressed to Indian Prime Minister Nehru dated October 24, 1959. In a letter dated November 7, Zhou told Nehru that the LAC consisted of "the so-called McMahon Line in the east and the line up to which each side exercises actual control in the west". China officially disputes the International Boundary between India and China in Jammu and Kashmir. As there is no commonly delineated Line of Actual Control (LAC) between India and China, there are a few areas along the border where India and China have different perceptions of the LAC including territory in Southern Tibet (which India calls Arunachal Pradesh). Both sides patrols upto their respective perceptions of the LAC due to perceived differences in alignment of LAC. The areas along the LAC are kept under constant surveillance by regular patrolling by troops and other means. Specific incidents of transgressions due to differences in the perception of LAC are taken up with the Chinese side through established mechanism such as Hot Lines, Flag Meetings, Border personnel Meetings and normal diplomatic channels.