His first bilateral visit outside the region was to Japan, and Japanese Prime Minister Shinzo Abe made a two-stop tour of South Asia earlier this month, pre-empting Xi's trip to the region this week.
"Complete shift in thinking"
After taking office, Modi moved quickly to appoint a former army chief as a minister for the northeast border region to accelerate development.
The road building plan marks a significant expansion of infrastructure in far-flung Arunachal Pradesh, a rugged, mountainous, 84,000 square kilometers (32,400 square mile) region that China calls South Tibet.
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China has vastly improved roads and is building or extending airports on its side of the border in Tibet.
According to a 2010 Pentagon report, it had placed nuclear-capable intermediate missiles in the area and deployed around 300,000 troops across the Tibetan plateau.
The Modi government's roads program could aid plans to establish a mountain strike corps of 80,000 troops who can move easily along its border.
The world's two most populous nations fought a brief frontier war in the area in 1962, and Chinese maps still show all of Arunachal Pradesh within China's borders.
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Indian efforts at development in the region have been relatively restrained in recent years. In 2013, Modi's predecessor announced plans for 850 kilometers (530 miles) of new roads in the border region, and proposals to upgrade airfields made little headway.
Previous governments deliberately neglected infrastructure in Arunachal Pradesh, partly to create a natural buffer against any Chinese invasion. That policy was dropped when the extent of development on China's side became clear.
"This is a complete shift in strategic thinking," said Namrata Goswami, a research fellow at the Delhi-based Institute for Defense Studies and Analyses.
Dependence and distrust
The neighbors have a complicated relationship marked by growing economic ties but also distrust, particularly over their unresolved territorial disputes.
The two armies were locked in a three-week standoff in May 2013 in the western Himalayas after Chinese troops set up a camp at least 10 kilometers (6 miles) inside territory claimed by India, triggering calls that India should stand up to its neighbor.
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Speaking in Beijing recently, Indian National Security Advisor Ajit Doval, a hawkish former spy chief who has in the past expressed doubts about China's motives, said the two nations' disputed border would be discussed during Xi's visit.
"Both sides have agreed to take steps to ensure the peace and tranquility of the border, and seek a fair, reasonable resolution both sides can accept on the basis of peaceful, friendly talks and consultations," Chinese Foreign Ministry spokeswoman Hua Chunying told a news briefing on Thursday.
Under the easing of environmental rules, Javadekar said road building within 100 km of the "Line of Actual Control" - the de facto but disputed border between India and China - would be brought under a single general approval scheme, while the amount of reforestation required would be lowered.
India is also pushing ahead with a proposal for electricity projects in states bordering China, and has said it will continue even if international development agencies which had earmarked cash to support the underdeveloped region do not back schemes in areas claimed by China.