Itanagar/ New Delhi | A woman from Arunachal Pradesh, who lives in the UK, alleged that immigration officials at China's Shanghai airport detained her for nearly 18 hours after refusing to recognise her Indian passport during a transit halt, raising concerns over Beijing's repeated attempts to challenge India's territorial sovereignty.

Pema Wangjom Thongdok, who was travelling from London to Japan on November 21, claimed her three-hour scheduled layover turned into a traumatising ordeal after immigration personnel declared her passport "invalid" solely because it listed Arunachal Pradesh as her birthplace.

Following the incident, India firmly conveyed to the Chinese side that Arunachal Pradesh is "indisputably" an Indian territory and its residents are perfectly entitled to hold and travel with Indian passports, government sources said.

Pema, whose family hails from Rupa in West Kameng district, claimed that Chinese officials insisted Arunachal Pradesh was "part of China" and demanded she accept their interpretation before allowing further processing.

In a detailed post on X on Sunday, she claimed, "I was held at Shanghai airport for over 18 hours on 21st November 2025 by China immigration and China Eastern Airlines. They called my Indian passport invalid because my birthplace is Arunachal Pradesh, which they claimed is Chinese territory."

Pema, 35, claimed that she was confined to the transit area without clear explanations, access to proper food, or basic facilities.

She also claimed that her passport was confiscated, and she was prevented from boarding her connecting flight to Japan despite carrying a valid visa.

What should have been a routine transit, she said, turned into a distressing standoff with airport authorities.

Sources said a strong demarche (a formal diplomatic protest) was made with the Chinese side, in Beijing and in Delhi, on the same day the incident took place.

The Indian consulate in Shanghai also took up the matter locally and extended the fullest assistance to the stranded passenger, they said.

"It was stressed that the passenger had been detained on ludicrous grounds. Arunachal Pradesh is indisputably Indian territory, and its residents are perfectly entitled to hold and travel with Indian passports," one of the sources said.

"It has also been highlighted that the actions of the Chinese authorities are in contravention of the Chicago and Montreal Conventions relating to civil aviation," the source said.

At a time when both sides are working on restoring normalcy, such actions by the Chinese side introduce unnecessary obstructions to the process, sources said.

Speaking to PTI, her mother Sang Chhom Thongdok said Pema went through a "harrowing ordeal", but she is "very smart and strong" and didn't buckle under pressure.

"After the issue cropped up, she first reached out to her late father's friend in Delhi, who helped her get in touch with the Indian embassy authorities in China, and they, in turn, helped her travel out of China. She is currently in Bangkok, Thailand," she said.

Pema has written to Prime Minister Narendra Modi, Union Minister Kiren Rijiju and Arunachal Pradesh CM Pema Khandu, she said.

Thongdok said her daughter spent her formative years in the national capital, studied B.com from a prestigious college under Delhi University, and went to a UK university for higher studies.

"My daughter has been living in the UK for nearly 10 years, but she is an Indian citizen. She works for a financial firm and travels frequently, but had never faced such an issue at any airport before," she said.

Thongdok said the family has a flat in the national capital too, and after her husband's death due to Covid-19 in 2021, she divides her time between her native place and Delhi.

The incident comes in the backdrop of China's long-standing and frequently reiterated claim over Arunachal Pradesh, which it refers to as 'South Tibet'. India has consistently rejected these claims, asserting that the state is an integral and inalienable part of the country.

Beijing has often attempted to reinforce its stance through diplomatic and administrative provocations, drawing strong reactions from India.

Incidents such as renaming villages in Arunachal, issuing 'standard maps' claiming Indian territory, and objecting to Indian leaders' visits to the state have repeatedly strained bilateral relations.

This incident also echoes China's long-criticised practice of issuing stapled visas instead of stamped visas to residents of Arunachal Pradesh, an act India has denounced as an affront to its sovereignty.

Several athletes, students, and officials from the state have previously been denied entry into China after refusing stapled visas, prompting India to protest and even cancel bilateral exchanges on multiple occasions.

These recurring actions have often sparked public anger within the state and triggered diplomatic warnings from New Delhi, which maintains that China must respect the sensitivity of the border issue and refrain from such unilateral measures.

Thongdok's experience has reignited concerns that China may be extending its stapled-visa logic to international transit points, potentially targeting travellers from Arunachal Pradesh even when they are simply passing through Chinese airports, an official in Itanagar said.