NEW DELHI/DUBAI China is pressing India to restart direct passenger flights after a four-year halt, but New Delhi is resisting as a border dispute continues to weigh on ties between the world's two most populous countries, officials said.

India-China relations have been tense since the biggest military confrontation in decades on their disputed Himalayan border killed 20 Indian and at least four Chinese soldiers in June 2020. Thousands of troops remain mobilised on each side.

Since the clash, India has made it difficult for Chinese companies to invest, banned hundreds of popular apps and severed passenger routes, although direct cargo flights still operate between the Asian giants.

Direct flights would benefit both economies, but the stakes are higher for China, where a recovery in overseas travel after the Covid-19 pandemic is lagging, while India's aviation sector booms.

Several times over the past year or so, China's government and airlines have asked India's civil aviation authorities to re-establish direct air links, two people with direct knowledge of the matter told Reuters, with one saying China considers this a "big issue".

"We hope the Indian side will work with China in the same direction for the early resumption of direct flights," China's Foreign Ministry told Reuters in a statement last week, adding that resuming flights would be in both countries' interests.

But a senior Indian official familiar with India-China bilateral developments said of Beijing's desire to resume flights: "Unless there is peace and tranquillity on the border, the rest of the relationship cannot move forward."

Indian airlines are holding discussions with New Delhi, while Chinese carriers are talking to their government about resuming direct routes, chief executive officer Pieter Elbers of Indigo, India's largest airline, told Reuters.

India's external affairs and civil aviation ministries did not respond to requests for comment.

Beijing has repeatedly protested India's ramped up scrutiny of Chinese businesses since 2020. Chinese smartphone giant Xiaomi told India's government this year that "confidence building" measures were needed as component suppliers were wary about setting up in India, citing compliance and visa issues.

Direct India-China flights peaked in December 2019, with a total of 539 scheduled flights by the likes of IndiGo, Air India, China Southern, China Eastern, Air China and Shandong Airlines, data from aviation analytics firm Cirium shows.

Chinese carriers scheduled 371 of those flights, more than double the 168 by India's airlines.

Flights were halted four months later as the pandemic escalated. Except for a smattering of Covid repatriation flights, they have not resumed even though India lifted Covid restrictions on international air routes a year later and China lifted all Covid travel measures in early 2023.

Travellers must now change planes either in Hong Kong, which has a separate aviation regulator and border controls from the rest of China, or in hubs like Dubai or Singapore.

This has lengthened the India-China journey from less than six hours to upwards of 10, handing business - including lucrative through traffic to the US - to carriers like Emirates, Singapore Airlines and Cathay Pacific.

The recovery in Chinese overseas travel is lagging due to rising costs and difficulties in securing visas for the world's top spenders on international tourism and airlines.

Indigo's Elbers said a recent interview in Dubai, "When the time is right and the governments come to a mutual understanding of how to move forward, we'll assess the market."

IndiGo flies seven times a week on the Delhi-Hong Kong route, where passengers can connect to mainland China.

Air India CEO Campbell Wilson said direct India-China flights "would seem to be a huge potential market" but for now there are factors at play "beyond our level".

  - Reuters