India has issued a firm démarche to China in both Beijing and New Delhi after an Indian woman from Arunachal Pradesh was stopped during her transit at Shanghai airport and kept there for more than 18 hours, and the incident has caused strong concern within Indian authorities.

The woman, Pema Wangjom Thongdok, later said that Chinese officials told her that her Indian passport was not valid. She said they humiliated her by insisting that Arunachal Pradesh is “China”.

“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. It was stressed that the passenger had been detained on ludicrous grounds,” according to sources.

“Arunachal Pradesh is indisputably Indian territory, and its residents are perfectly entitled to hold and travel with Indian passports.”

Thongdok, an Indian citizen who has lived in the UK for more than ten years, was held by Chinese authorities at Shanghai airport while travelling from London to Japan. In her comments to ANI, she said that officials pulled her out of the queue and told her that her passport was invalid. She said that they were “mocking her” and even told her to apply for a Chinese passport.

Indian officials later reached out to her and resolved the matter.

“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,” according to the sources on the Indian side.

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

The incident comes at a time when India and China are trying to stability their relationship after more than four years of hostility following the Galwan clashes in 2020.

China has continued to claim Arunachal Pradesh as its territory, and India has repeatedly rejected this claim by stating that the state is an indisputable part of India.

China on Tuesday dismissed the allegation that an Indian woman from Arunachal Pradesh was harassed during her layover at Shanghai airport. However, Chinese Foreign Ministry used the incident to again push Beijing’s claim over the state, which it calls Zangnan.

When asked about the incident, Chinese Foreign Ministry spokesperson Mao Ning denied wrongdoing and said that Thongdok “was not subjected to any compulsory measures, detainment or harassment.” Mao said that border officials acted “according to laws and regulations” and that the airline had arranged a place to rest along with food and water, and Mao repeated China’s claim with the statement “Zangnan is China’s territory. China never acknowledged the so-called Arunachal Pradesh illegally set up by India.”