The detention of Pema Wangjom Thongdok, an Indian citizen living in the UK, at Shanghai airport provoked a diplomatic row between Delhi and Beijing.
Ms Thongdok said she was detained by immigration officials while traveling from London to Japan via Shanghai last Friday because her passport listed her place of birth as the north-eastern state of Arunachal Pradesh.
China disputes India's claims to the region and claims Arunachal as its territory, calling it “Southern Tibet” – a claim India strongly rejects.
Tuesday India said he lodged a protest against Ms Thongdok's detention and affirmed that Arunachal was an “integral and inalienable” part of India.
Ms Tongdok, who called the experience “humiliating”, sought help from the Indian embassies in Shanghai and Beijing. She was released from custody 18 hours later when Indian officials arrived at the airport and spoke with authorities.
India's foreign ministry spokesman Randhir Jaiswal called Ms Thongdok's detention “arbitrary” and said the issue had been actively discussed in China.
“The Chinese authorities have still failed to explain their actions, which violate several conventions governing international air travel. Their actions also violate their own rules, which allow visa-free transit of up to 24 hours for citizens of all countries,” he said in a statement.
Mr Jaiswal's statement came hours after Chinese Foreign Ministry spokesman Mao Ning said China's border control authorities had “carried out inspections in accordance with laws and regulations.”
“Law enforcement agencies were impartial and did not abuse the legal rights of individuals. [Ms Thongdok] were fully protected, no coercive measures were taken against her, there was no so-called “detention” or “harassment,” she told the Indian news agency PTI. She added that China Eastern provided Ms. Tongdok with accommodation and food.
But she insisted that Arunachal was Chinese territory.
“The Chinese side has never recognized the so-called 'Arunachal Pradesh' illegally created by India,” she said.
The state, which lies along a 3,440-kilometer (2,100-mile) Himalayan de facto border called the Line of Actual Control, has been a source of tension between the Asian neighbors for decades.
China says it claims all of Arunachal Pradesh as its territory, while India claims the Aksai Chin plateau in the Himalayas, which is controlled by China.
Troops from countries Clashes broke out along the border in Tawang in Arunachal Pradesh in 2022. The brawl occurred at a time when India and China were working to restore ties after the Galwan Valley clash in the Ladakh region in 2020 led to a complete breakdown in ties.
Over the last year or so, India and China have taken several major steps to normalize relations, including resumption of air traffic with each other's countries and agreeing on patrol arrangements to reduce border tensions.
In August, Chinese Foreign Minister Wang Yi, who was in Delhi on a two-day trip, said that neighbors must view each other as “partners” and not as “adversaries or threats.”.
Thus, Ms. Thongdok's detention amid these friendly efforts raised eyebrows in India and made national headlines.
She said She told news agency ANI that she had lived in the UK for 14 years and had previously traveled to Shanghai several times without encountering any problems.
This time, however, an immigration officer at the airport “singled” her out of the queue and told her her passport was invalid, she said.
“When I tried to interrogate them and ask what the problem was, they said, 'Arunachal is not part of India' and started mocking, laughing and saying things like, 'You should apply for a Chinese passport, you are Chinese, you are not Indian,'” she added.
