China has further loosened restrictions over its northern airspace, giving airlines a flexible choice of entry into the country on the day of flight.

A new policy announced Wednesday by the General Administration of Civil Aviation of China (CAAC) allows airlines traveling between North America and China a choice of three entry points and four cross-polar routes no later than one hour before take-off.

Previously, international flights had to follow one fixed route and had to give six months notice of change.

The new policy provided an effective solution for the cross-polar flights with regard to safety and efficiency, said Su Langen, deputy director of air traffic control under the CAAC.

The new policy was put into effect at the end of June, but was only announced Wednesday when the number of flights returned to the level before the severe acute respiratory syndrome (SARS) crisis.

In 1996, four routes across the Arctic linking North America and Asia were agreed upon by the civil aviation authorities of China, Mongolia, Russia, Canada and the United States under the guidance of the International Air Transport Association (IATA).

For flights between North America and Asia, the cross-polar routes offer significant savings, while the new policy allows safety, legal and efficiency issues to be considered on the day of flight.

China had made great contributions to achieving safe, efficient non-stop flights between North America and Asia, said David Behrens, director of safety, operations and infrastructure of IATA Asia and Pacific.

He said the new policy would attract more airlines to the cross-polar routes and considerably enhance ties between the two continents.

The new policy would lead to a 40-plus minute reduction in flight times on cross-polar routes, said Xu Chaoqian, of the Air Traffic Management Division of the CAAC.

"The stand of the Chinese government also indicates mutual understanding between East and West," said Prof. Shi Yinhong, with the International Relations Institute in the Beijing-based .