A high-altitude tunnel is latest flashpoint in India-China border tensions 
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A tunnel constructed high in the mountains of northeastern India has become the latest flashpoint in a simmering border dispute between New Delhi and Beijing. 
 
The Sela Tunnel, inaugurated by Indian Prime Minister Narendra Modi earlier this month, has been hailed in India as a feat of engineering – blasted through the Himalayas at an elevation of some 13,000 feet (3,900 meters) – and a boon for the military, enabling faster, “all-weather” access to a tense de facto border with China. 
 
That’s caught the attention of Beijing, whose long-running dispute with New Delhi over their contested 2,100-mile (3,379-kilometer) border has seen the two nuclear-armed powers clash in recent years. 
 
That includes in 2020 when hand-to-hand fighting between the two sides resulted in the deaths of at least 20 Indian and four Chinese soldiers in Aksai Chin-Ladakh in the western stretches of the border. 
 
And, decades ago, the dispute led to war. 
 
China also claims the Indian state of Arunachal Pradesh, where the tunnel was constructed, as its own, even as the area has long functioned as Indian territory. 
 
Chinese officials in recent days have slammed the tunnel project and Modi’s visit to the state, accusing New Delhi of taking steps to undermine peace along the border. 
 
“We require the Indian side to cease any action that may complicate the boundary question … the Chinese military remains highly vigilant and will resolutely defend national sovereignty and territorial integrity,” a Defense Ministry spokesperson said last week, using the Chinese name “Zangnan” or South Tibet to refer to Arunachal Pradesh.