A three-nation European team aiming to be the first balloonists to fly round the world non-stop might have to give up if China does not let them cross over its territory, mission officials said yesterday.As the trio aboard the Breitling Orbiter-II drifted slowly across southern Afghanistan towards Pakistan waiting for news from Beijing, intense diplomatic and private efforts were under way to get a Chinese go-ahead."It all depends on the Chinese now," said a spokesman at the Geneva airport control centre for the flight, now in its sixth day since lift-off from the Swiss Alps.Although controllers were plotting alternative routes taking the Orbiter down across India and south-east Asia, the team was known to be unhappy about flying over (and in emergency having to come down in) dense forest areas.Mission leader Bertrand Piccard, a Swiss psychiatrist, said in a radio interview from the balloon: "It would be marvellous if we could cross China."The Orbiter needs to take advantage of the high-level jetstream winds that would propel it beyond Chinese territory within 18 hours and out across Japan into the Pacific. These winds do not blow farther south.Although the men took off last Wednesday with China saying it could not guarantee the balloon's safety and declining to give clearance, they had been confident that by now Beijing would have relented."We hope they [the Chinese] realise the balloon is not dangerous," said a mission spokesman.In his radio interview, Piccard (39), was philosophical. "When you go visiting someone, you knock on the door . . . but you don't force it open," he said.The absence of a green light from Beijing had earlier forced Piccard and his crew - Belgian pilot Wim Verstraeten and British engineer Andy Elson - to drop down out of the jet stream while clipping along over Iran.If they had stayed at the 9,000 metres (21,000 feet) where the stream was driving them eastwards, they would have been taken into China with or without permission at a speed of up to 230 km an hour.But after descending to around 3,000 metres, their speed dropped from over 100 km an hour to 15 to 50 km an hour.Controllers had hoped that China would match the goodwill shown by Iraq at the weekend.Despite advance permission from Iran for an overflight, however, there were some tense moments over that country when the national Air Force said the team had to land at an airbase. After a period of arguing by radio, the crew eventually got the go-ahead to continue its flight.Even if the crew decides to veer southwards away from China, that manoeuvre would add at least two days to what was originally planned as a 14-day voyage, stretching fuel supplies close to the limit.