At least one other school has cancelled an outdoor sports event because of fears that poor air quality could harm students’ health.

An inter-house cross-country event by South Island School, scheduled for yesterday afternoon, had to be postponed to October 5.

The secondary school in Southern District, run by the English Schools Foundation, attributed the postponement to poor air quality.

A message on the school’s website read: "Today’s [September 21] inter-house cross-country is postponed due to the high pollution."

Hong Kong has been veiled behind thick smog this week, with the Air Pollution Index at high levels.

On Wednesday the Chinese International School cancelled its annual swimming gala in Victoria Park because of smog. The event was relocated from the public swimming pool to the school’s indoor pool, making it impossible for hundreds of students to attend

.

The pollution index at the Causeway Bay roadside station on that day remained around the "very high" level of 110 throughout the morning and early afternoon.

On Monday primary pupils at the Kennedy School in Pok Fu Lam were asked to stay indoors to have lunch, also because of poor air quality and high temperatures. And the West Island School in Pok Fu Lam relocated a physical education class to the school’s indoor sports ground.

There was no sign of significant improvement in air quality yesterday. The pollution index at the Central roadside station hit the "very high" level of 106 at 7am and only dropped to "high" at 96 by 7pm.

But the Canadian International School’s cross-country run was given the go-ahead yesterday.

A spokesman for the school said it was satisfied with the air quality in the area and had decided to run the race in Aberdeen Country Park.

"The event went ahead as scheduled. We have taken into consideration the air pollution and the sky was clear," the spokesman said.

"The pollution levels on this side of the island are very different from those in Central, partly because there is not so much traffic."

He also said the secondary school had received no complaints from students or parents.

In June the Council for Sustainable Development released a report on possible solutions to air pollution in Hong Kong. Among the key proposals were adopting road pricing and letting schools suspend classes on heavily polluted days.

The consultation is expected to end on October 15.

An Education Bureau circular issued in 1998 advised that sports days or swimming galas in affected areas be cancelled when the air pollution index reached 201.