India has issued a demarche to China after a woman from Arunachal Pradesh alleged that she was detained at the Shanghai airport by immigration officials for 18 hours, who “mocked” her and said that the territory was not part of India, according to Indian media.

China says Arunachal Pradesh is a part of South Tibet — a claim India has repeatedly dismissed. Beijing has renamed places in the northeastern Himalayan state multiple times, prompting strong reactions from New Delhi.

The woman, named Pema Wangjom Thongdok, said in yesterday’s interview to ANI that she was an Indian citizen residing in the United Kingdom for about 14 years. Thongdok said she was travelling from London to Japan’s Osaka via Shanghai on November 21, when Chinese authorities held her back for 18 hours.

Detailing her “very long ordeal”, Thongdok alleged that Chinese immigration officials at the Shanghai Pudong International Airport declared her visa as “not acceptable” and her Indian passport as invalid.

She further said the officials “mocked” her, saying Arunachal Pradesh was not a part of India.

“You’re Chinese, you’re not Indian,” the woman quoted them as saying.

“The airline staff of China Eastern and about two other immigration officers were speaking in their language and saying […] ‘Arunachal’ and laughing and calling it ‘China, not India’,” Thongdok told ANI, describing the immigration and airline staff’s behaviour as “very humiliating [and] questionable”.

Frustrated by their conduct, she reached out to the Indian embassies in Shanghai and Beijing, resulting in officials intervening to help her leave the country.

“We are part of India … We speak ‘shuddh Hindi’, we don’t understand C of Chinese, we are all Indian,” Thongdok told ANI.

“They called my Indian passport invalid as my birthplace is Arunachal Pradesh, which they claimed is Chinese territory,” Thongdok had said on social media platform X on November 23 (Sunday), referring to Chinese immigration officials and China Eastern Airlines’ staff.

On Monday, The Print quoted a source as saying that a “strong démarche was made with the Chinese side, in Beijing and in Delhi, on the same day the incident took place”.

“Our consulate in Shanghai also took up the matter locally and extended the fullest assistance to the stranded passenger,” the source added, terming Thongdok’s detention based on “ludicrous grounds”.

“Arunachal Pradesh is indisputably Indian territory, and its residents are perfectly entitled to hold and travel with Indian passports,“ they added, according to the publication.

Other Indian publications, including Press Trust of India, Hindustan Times, The Wire and ANI, also reported the same, citing sources familiar with the matter.

Following the incident, Thongdok wrote to India’s Prime Minister Narendra Modi, Arunachal Pradesh Chief Minister Pema Khandu, the Ministry of External Affairs (MEA) and the foreign secretary, asking them to ensure that any Indian citizen does not face such a situation in the future, The Statesman reported.

The incident comes as both China and India, for the past year, have been seeking to put aside differences lingering since their 2020 border standoff.

Sources in India’s MEA, as per The Hindu, said that at a time when both sides were working to improve ties, such actions by the Chinese side introduced unnecessary obstructions to the process.