Travel to and from China is opening up - and picking up pace quickly. By Mark MacKenzie

Earlier this year, Beijing hosted its second annual International Travel and Tourism Market (BITTM). During the three-day event, established to promote travel between China and the rest of the world, figures emerged that seemed to confirm what the travel industry already knew: that the sleeping giant that is China's tourism market is rapidly waking. Last year, an estimated 31 million leisure travellers departed from Chinese airports. By 2020, that figure is expected to more than treble to 100 million a year.

It's worth pointing out that, until 2000, the Chinese authorities looked less than favourably on citizens wanting to holiday abroad. But for the past six years those nations keen to attract Chinese visitors have been able to apply for Approved Destination Status (ADS), where the Chinese and other governments effectively agree to promote one another as destinations.

ADS imposes strict conditions to prevent Chinese travellers absconding (including the lodging of hefty deposits before travel), with Britain joining the scheme last year. So far, 118 countries have ADS and regions investing heavily in the market include Australasia and Europe. In March, Scotland launched a campaign to attract golfers from China to its famous links in response to predicted revenues of £70m over four years.

The burgeoning market is a two-way street, according to Karen Taylor, event director for BITTM. "Last year, around 120 million travellers visited China," she says, "and most headed for traditional sights in main cities." Ms Taylor is referring to landmarks such as the Great Wall, yet she believes the choices available to incoming tourists can only grow. In part, this is due to a new breed of "megacities" - rapidly expanding conurbations such as Chongqing, Wuhan and Nanjing. And, "with the Beijing Olympics [in 2008] and the World Expo in Shanghai [in 2010], it's likely we'll see more and more diverse tourism".

Chongqing authorities recently announced that over the next decade, tourism will become a "pillar industry". By 2010, revenues from visitors are expected to reach £3.5bn - Chongqing has more than 130 hotels and restaurants authorised to receive foreigners, staffed by a workforce of 80,000.

So it's no surprise that China's aviation infrastructure is among the fastest growing in the world. Plans are well advanced to build 48 airports in the next five years, bringing the total to 200. During the Olympics, international visitors will be welcomed at the world's largest airport terminal, with capacity to handle 35 million passengers a year. Last year, British Airways began flying five times a week to Shanghai, complementing existing routes to Hong Kong and Beijing. "We're always looking for new routes," says Laura Goodes, of BA. "Shanghai, for example, is increasingly somewhere to visit for a long-weekend."

But such rapid growth may come at a price. In addition to concerns about China's human rights record, the world's press recently carried stories about the environmental damage wreaked by its monumental industrial expansion. The state Xinhua news agency even took the unprecedented step of reporting that the Yangtze River delta, thought too large to pollute, is enduring a not-so-slow death. Supplying water to 400 million people, including Shanghai, the near 4,000-mile river is a dumping ground for so much untreated sewage that 70 per cent of its water could be unusable by 2011.